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I The Determinants and Evolution of Major Inter-firm Transactions in the U.S. Apparel Sector Xiao (Mimosa) Zhao Supervisor: Margaret Dalziel Thesis submitted to the Faculty of Graduate and Postdoctoral Studies in partial fulfillment of the requirements for the M.Sc. degree in Management Telfer School of Management University of Ottawa © Xiao Zhao, Ottawa, Canada, 2013

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Page 1: The Determinants and Evolution of Major Inter-firm ... · The Determinants and Evolution of Major Inter-firm Transactions in the U.S. Apparel Sector Xiao (Mimosa) Zhao Supervisor:

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The Determinants and Evolution of Major Inter-firm

Transactions in the U.S. Apparel Sector

Xiao (Mimosa) Zhao

Supervisor: Margaret Dalziel

Thesis submitted to the

Faculty of Graduate and Postdoctoral Studies

in partial fulfillment of the requirements

for the M.Sc. degree in Management

Telfer School of Management

University of Ottawa

© Xiao Zhao, Ottawa, Canada, 2013

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Acknowledgements

I express my gratitude to those who help me to complete my thesis and my Master degree

in Telfer School of Management. I will be forever grateful for the tremendous supervision,

support, and encouragement that they collectively and individually provided to me

throughout my journey at Telfer.

First, I would like to sincerely thank my beautiful thesis supervisor Margaret Dalziel.

Working with her has become one of the most splendid experiences in my life. Margaret

did not only help me with research and thesis, but also provided enormous advice on my

life and career, which helped me through many challenges, and which I appreciate deeply.

I enjoyed the chatting with her on topics about choice of life and career, jazz music, China,

travels, and even good food. To me, Margaret is much more than an advisor who

supervised my thesis, but also a great friend and a family. She is a mentor for my research

as well as a role model for my life.

I am also grateful to my insightful and generous committee members – Prof. Freel and Prof.

Chamberlin. Thanks for the valuable comments from them on my thesis. I am also indebted

to Prof. Ajax who supported me to ASAC conference and helped on my Statistics course.

I would like to thank all my friends in Canada who make my life much easier and happier

and share the time with me. Especially, the encouragement and support from Wangzhe Li

and Yuxuan Song have helped me to go through many challenges. I would also like to

thank Prof. Yang and Prof. Luo who helped me with my thesis in Waterloo.

My gratitude also goes to my cousin's family. Thanks to their support in Toronto and

provide me with a second home. I enjoyed the Christmas holiday with them.

My thesis is dedicated to my parents. Without their love and support, I will never achieve it

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and enjoy the happiness of life when I am alone far away from home.

感谢我的爸爸妈妈,教会我享受生活,开心做人。

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Abstract

This study provides a systematic description of the nature and evolution of major

transactions in the U.S. apparel sector, using a theory that applies across sectors. This

research investigates the determinants of the existence and magnitude of major inter-firm

transactions, relying on a unique longitudinal dataset of over 2,000 of the largest

transactional (buy-sell) relations between publicly traded firms in the U.S. apparel sector.

The results indicate the importance of inter-firm complementarity, rather than inter-firm

similarity, in explaining the sector architecture; thus contributing to the future

improvement of industry classification systems. This study also contributes to a deeper

understanding of the apparel sector focusing on the change in the relative importance of

manufacturing activities versus service activities and in the involvement of firms from the

outside apparel sector. Implications of inter-firm transactions are discussed regarding

industry policies, and human and environmental welfare in manufacturing and raw

materials industries.

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Table of Contents

Acknowledgements ...................................................................................................... II

Abstract ...................................................................................................................... IV

Table of Contents ......................................................................................................... V

List of Tables ............................................................................................................. VII

1. Introduction ...........................................................................................................1

2. Literature Review ..................................................................................................7

2.1 Theories that Explain Firm Scope ............................................................7

2.2 Industry Architectures ...............................................................................9

2.3 Transactions ..............................................................................................13

2.4 Global Value Chains ................................................................................14

2.5 Industry Classification ............................................................................16

3. Theoretical Development ....................................................................................21

3.1 Theory .......................................................................................................21

3.1.1 Similarity ...........................................................................................21

3.1.2 Complementarity ..............................................................................24

3.2 Hypothesis Development .........................................................................26

3.2.1 The Determinants of Major Inter-firm Transactions ....................27

3.2.2 The Evolution of the Apparel Sector ...............................................31

4. Methodology ........................................................................................................35

4.1 Data ...........................................................................................................35

4.1.1 Data Preparation ..............................................................................35

4.1.2 Data of Apparel Sector .....................................................................36

4.1.3 Apparel Sector Roles ........................................................................37

4.2 Measures ...................................................................................................46

4.2.1 Dependent Variables .........................................................................46

4.2.2 Independent variables ......................................................................46

4.2.3 Control Variables ..............................................................................49

4.2.4 Descriptive Statistics and Correlation Matrix ...............................52

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4.3 Analytical Approach ................................................................................55

4.3.1 Fixed Effect Models ..........................................................................55

4.3.2 Random Effect Models .....................................................................55

4.4 Descriptive Statistics ................................................................................57

4.4.1 Data Records .....................................................................................57

4.4.2 Number of Unique NAICS Codes (4-digit level) per Year ............59

4.4.3 Number of Transactions and Value of Transactions ......................59

5. Results ..................................................................................................................61

5.1 Determinants of the Presence of Inter-firm Transactions ....................61

5.2 Determinants of the Magnitude of Inter-firm Transactions ................64

5.3 Comparison of Results .............................................................................66

5.4 Evolution of Apparel Sector ....................................................................71

6. Conclusion ............................................................................................................75

6.1 Contributions ...........................................................................................75

6.2 Implications ..............................................................................................77

6.3 Limitations and Future Research Directions ........................................80

References………………………………………………………………………….. 81

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List of Tables

Table 4.1 Central Roles in Apparel Sector………………………………………….….. 37

Table 4.2 External Roles with Frequencies of Appearance over 20………………….… 38

Table 4.3 Degree of Dependency of Sector Roles of Firms………………………....….. 46

Table 4.4 Summary of Variables and Measures……………………………………..….. 51

Table 4.5 Descriptive Statistics and Correlation Matrix…………………………..……. 53

Table 5.1 Logistic Regression of the Existence of Transaction on NAICS Proximity and

Dependency…………………………………………………………………..…………. 68

Table 5.2 GLS Regression of the Magnitude of Transaction on NAICS Proximity and

Dependency………………………………………………………………………...…… 69

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List of Figures

Figure 3.1 Quadrant for Similarity, Complementarity, Intra-firm and Inter-firm

Relations…………………… …………………………………………………….……..18

Figure 4.1 Number of Unique Firms with Revenues…………………………….……....36

Figure 4.2 Transactional Network by NAICS Code (3-digit)…………………………....40

Figure 4.3 Transactional Network by NAICS Code (2-digit)…………………………....41

Figure 4.4 Transactional Network by Sector Role…………………………………….....42

Figure 4.5 Seller-Buyer Design Matrix Structure……………………………………..…43

Figure 4.6 Number of All Firms and Firms from Manufacturing, Service, and External

Sectors Every Five Years………………………………………………………….……..57

Figure 4.7 Trend per Five Years for Number of Unique NAICS Codes (4-digit level) of

Sellers, Buyers and Total Firms…………………………………………………..……...58

Figure 4.8 Trends for Number of Transactions and Value of Transactions…………..…..59

Figure 5.1 Proportion of Service Firms versus Manufacturing Firms………………..….71

Figure 5.2 Proportion of External Firms versus All Firms………………………….…...72

Figure 5.3 Proportion of Non-regular Transactions versus Regular Transactions…….....73

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1. Introduction

Transactions are the most basic form of inter-firm relationship and are a fundamental

unit of economic analysis (Williamson, 1975). Within a sector, transactions in

intermediate markets serve to link and coordinate complementary activities across

firms (Jacobides & Winter, 2005; Baldwin, 2008). Research on transactions has

focused on the question of how a transaction will be governed. Transaction-cost

economics considers the firm’s decision as to whether to make or buy a particular

input (Williamson, 1975). Transaction costs are the costs associated with using

suppliers in the outside market rather than producing in-house. Opportunistic

transaction costs have been the focus of Williamson’s transaction costs economics,

while Baldwin (2008) places the emphasis on mundane transaction costs. Specifically,

opportunistic transaction costs plus mundane transaction costs are together equal to

the total transaction costs. Baldwin (2008) illuminates the importance of mundane

transaction costs, which are defined as “the costs of defining, counting and

compensating for things transferred”. The theory of mundane transaction costs

determines whether a transaction is possible, and argues that transactions are only

possible at thin crossing points between modules.

An inter-firm transaction is a basic business event and transactional relationships

impact firm prospects. Cohen and Frazzini (2008) show that customer-supplier

relationships generate significant co-movements in the underlying cash flows of

linked firms. A growing body of studies has investigated the impact of inter-firm

network structures on firm performance. Bonaccorsi and Giuri (2001) suggest that the

structural dynamics of the supplier industry depend on the ways in which inter-firm

transaction networks are created and distributed among vertically related supplier and

buyer industries.

A related and important question is where transactions are likely to take place. Given

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a pair of firms, how likely is it that they will be engaged in a buy-sell relationship and

in which direction will the transaction be oriented? At an inter-industry level,

economists have reversed the question such that inter-industry transactions are used to

generate information on the structure of the economy. Input-Output (I-O) models

produce fundamental knowledge of the structure of the economy and are used to

reconcile government accounting systems. In some cases, global value chains (GVCs)

indicate the likely transactional relations between firms. For example, firms are

associated with relatively clear global value chain roles in sectors (e.g. automotives,

apparel) that produce physical products.

The Chief Economist of Foreign Affairs and International Trade Canada considers

global value chains (GVCs) to be of high importance and observes that “measurement

has probably been the most significant obstacle to developing a better understanding

of GVCs” (DFAIT, 2011). Similarly, in a recent report published by the Institute for

Research on Public Policy (IRPP, 2012), new data are identified as the primary

requirement for acquiring a better understanding of Canada’s role in GVCs.

The requirement for additional data arises as a consequence of the limitations of the

standard industry classification systems used by governments. These systems group

industries together into subsectors and sectors on the basis of similarities in the nature

of activities performed by firms in neighbouring industries. But value chains and other

self-organized networks of firms such as sectors and ecosystems are composed of

firms that perform complementary activities to collectively address the demands of

final user-customers. So while we know a great deal about relations between

competing firms that perform similar activities in the same industry, it is difficult to

obtain information about relations between firms in different industries that are

engaged in complementary supplier-customer relations. Therefore, the questions

remain. These include the following:

- What role do service providers play in global value chains?

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- To what degree are firms outside the primary sector involved in the primary-sector

value chain?

- To what degree do transactions involve pairs of firms that have an

upstream-downstream relationship versus backward and cycled transactions?

- How stable are GVC relations over time?

It is of scientific importance to investigate why and where inter-firm transactions exist

because they help us to reveal the persistent pattern of inter-firm relations, and to

understand the structure of industry. I believe that large and persistent transactions

constitute the structure of the economy in the same manner as branches, not leaves,

capture the structure of trees. In the interest of developing a better understanding of

industry structure, I am conducting a study on the determinants of major inter-firm

transactions. In addition, it is of practical importance to know where inter-firm

transactions are likely to take place since transactions are firms’ fundamental

economic activities and are closely related to firms’ behaviours and level of

commitment to corporate social responsibility. Policymakers, firms and organizations,

and citizens should be aware of the impact of their economic activities on certain

critical issues such as human welfare and environmental welfare. For instance, the

disasters that took place in Bangladesh’s manufacturing industry have implications for

Western retailers and consumers in developed countries because their buying

behaviours have implications for labour and safety standards, including the

enforcement of building codes in Bangladesh (Strauss, 2013). Retailers and buyers,

though without official data, understand that their purchasing activities have

implications for other industries on which the retail industry depends; examples

include human-welfare issues in manufacturing industries or environmental issues in

raw materials and resource industries.

Governments have access to large quantities of data. But, because the data are

organized in an unhelpful way, governments cannot easily draw conclusions about

inter-industry or inter-firm relations from the data. They can only operate on the basis

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of the common knowledge that consumers have, or on the basis of sensational news

reported by the public media. If the data that governments have were organized in

such a way as to make evident the relationships between upstream and downstream

economic activities, then we would have scientific knowledge regarding the impacts

of consumers’ purchases on human and environmental welfare. A better understanding

of inter-firm transactions would be of benefit to international trade policy (e.g., tariffs

and quotas), the improvement of labour and safety standards, and the development of

industrial policy.

My empirical focus will be on the apparel sector and this selection is justified for

several reasons. First, the apparel sector has experienced transformation in its supply

chain due to the introduction of the “fast fashion” concept and of “lean retailing”

strategies, along with the adoption of new information technologies (Abernathy et al.,

2000). Gereffi, Humphrey, and Sturgeon (2005) indicate that the apparel industry has

shifted from a captive value chain to a more complex relational value chain. Second,

the apparel sector can be considered to be one of the most global of all industries

(Dickerson, 1995; Gereffi, 1999). Globalization has facilitated industrial upgrading

that involves organizational learning to improve the position of firms or nations in

global trade networks (Gereffi & Tam, 1998). Thirdly, many U.S. economic analysts

hold the popular prognosis that U.S. apparel manufacturing is dying (Abernathy et al.,

1995). Tassey (2010) points out that the United States has allowed the manufacturing

sector to languish. The plight of the manufacturing sector not only is an “industry”

problem but is also a “value chain” issue. Finally, since my study is at the starting

point to investigate sector architecture, the apparel sector is suitable for testing a

pioneering theory due to its relatively low complexity and long tradition.

This study describes the nature and evolution of major inter-firm transactions in the

U.S. apparel sector. I believe that the fundamental patterns in the nature of inter-firm

relations persist, notwithstanding the strategic behaviours of different firms, the

presence and absence of certain firms over time, and the diversity in business

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environments. Specifically, I will investigate the existence and magnitude of major

inter-firm transactions and will examine the structure and evolution of the U.S.

apparel sector over time.

My study sample relies on a unique longitudinal dataset of over 2,000 of the largest

transactional (buy-sell) relations between publicly traded firms in the U.S. apparel

sector over the last 35 years. This dataset allows me to characterize the determinants

and evolution of transactional networks. The data are available because the U.S.

Securities and Exchange Commission requires firms (including foreign firms) that are

publicly traded in the U.S. to report the percentage of their revenues that is

attributable to sales to a specific customer, in cases where those sales exceed 10% of

total revenues. I did not consider the minor inter-firm transactions because in general

large firms, rather than small firms, are more likely to construct and change the

structure of transactional networks. Moreover, small firms tend to follow the general

patterns and lack the capability to change the structure of industries.

This study only focuses on the apparel and apparel-related industries. Based on the

North American Industry Classification System (NAICS), I identify the following

subsectors: 313 (Textile Mills), 315 (Apparel Manufacturing), 316 (Leather and Allied

Product Manufacturing), 4243 (Apparel, Piece Goods, and Notions Merchant

Wholesalers), and 448 (Clothing and Clothing Accessories Stores); I also identify

observations where either the seller or the buyer operates in one of the

above-mentioned subsectors. Additional data on firms’ revenues are extracted from

Research Insight. The second dataset contains firm-year observations from 1992 to

2010.

My research questions are as follows:

- What factors predict the existence and magnitude of major inter-firm transactional

relationships?

- How does the U.S. apparel sector evolve over time?

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My results clearly show that inter-firm complementarity predicts both the existence

and magnitude of major inter-firm transactions better than inter-firm similarity. My

thesis is the first study that responds in a scientific manner to the need to examine

major transactions between firms and that employs a theory that is replicable across

different sectors. This study also contributes to a deeper understanding of the apparel

industry by focusing on changes in the relative importance of manufacturing activities

versus service activities and in the involvement of firms from outside the apparel

sector.

The thesis is organized as follows. Chapter 2 provides a brief review of five strands of

literature. Then I develop my theories and derive hypotheses in Chapter 3. In Chapter

4, a description of my data and methodology is presented. In Chapter 5, findings and

results are presented and discussed. The last chapter discusses the contributions,

limitations, and implications of my study.

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2. Literature Review

In this section, I provide a brief review of five strands of literature: 1) theories that

explain firm scope, 2) industry architecture, 3) transaction, 4) global value chains

(GVCs), and 5) industry classification. Each strand provides explanations for a better

understanding of industry architecture and its evolutionary path.

2.1 Theories that Explain Firm Scope

Vertical integration is a form of organizing from a firm-level perspective. Researchers

study vertical integration in terms of its theoretical issues and operational approaches.

It is relevant to my research because it deals with firm’s integration versus

specialization in terms of firm boundaries and it brings back the question of the

division of labor. Adam Smith (1776) argued that the division of labor is limited by

the extent of the market. The emergence of vertically integrated firms will redefine the

boundaries and generate re-division of labor among firms, and therefore transform the

architecture of industry as well as the whole economy. The overall trend is towards

specialization, although re-integration does occur.

Transaction cost economics. Transaction cost economics (TCE) theory particularly

focuses on the concept of vertical integration. As noted by Williamson (1975), the

main case in TCE is the issue of vertical integration. The core thesis of TCE is that

firm boundaries and the resulting levels of vertical integration are explained by

governance cost. Firms can choose to make the products that they need in-house or

buy them from outside suppliers. Transaction costs are the costs of governing make or

buy relationships. If government costs are high, the firms choose to make what they

need in-house, thus becoming more integrated. If the government costs are low, then

firms will buy from the outside market.

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Transaction costs largely depend on the risk of opportunistic renegotiation

(Williamson, 1975). The risk of opportunism occurs when a firm involved in a

transactional relationship has to make dedicated and long-term investments to ensure

the relationship works well but this investment will only be supportive to this

relationship but not in other environments. The firm is likely to be ‘held up’ by the

firm from the other party when it makes asset-specific investments. Knowing the

potential risk, it is difficult for any firm to make such a durable but asset-specific

investment and get the valuable return of such a risky investment unless the firms on

the other side guarantee no risk of opportunism. However, firms behave

opportunistically, and are unlikely to guarantee no opportunism. So, the main way to

achieve specialized investments is vertical integration (Williamson, 1985). According

to the TCE theory, when asset specificity is high, and hence transaction costs resulting

from risk of opportunism are high, firms will chose to become vertically integrated.

TCE scholars consider market failures owing to asset specificity as the main reason to

explain firm’s decision of vertical integration (Williamson, 1985). Numerous studies

have found positive influence of asset specificity on vertical integration and asset

specificity has shown to be the most significant TCE-based determinant of vertical

integration (Gulbrandsen et al, 2009).

Resource-based theory. Resource-based theory focuses on the unique internal

resources of a firm’s sustained competitive advantage. Firms will tend to specialize in

activities that their capabilities offer some competitive advantages (Richardson, 1972).

Barney (2000) created a resource-based model of sustained competitive advantage

and suggested that sources of sustained competitive advantage are firm’s resources

that are valuable, rare, imperfectly inimitable and nonsubstitutable. RBV assumes that

firms develop by integrating activities that are related to existing activities

(Richardson, 1972). In addition, Richardson (1972) is very specific about the

relationship amongst the types of activities firms will do internally and the types of

activities that will be done by the firms with whom they transact. Winter (1988) points

out the notion that firms grow by vertical integration through developing ‘something

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closely related’ instead of ‘more of the same’. He argues that where integration takes

place relies on the ‘degree’ of relevant resources and knowledge that firms already

had. Firms over time add activities that relate to some aspect of existing activities

(Teece et al, 1994). Based on RBV, as firms expand by vertical integration they grow

in the direction of something closely related to their existing resources, activities,

knowledge, experience and competency.

Following Winter (1988), the firm’s decision of integration should be assessed in

terms of the extent to which current resources and existing knowledge can be applied

to integrate a new activity. Coherence is a measure of relatedness proposed by Teece

et al (1994) and is exhibited by multi-product firms developing related lines of

businesses. It has shown that firms grow more diverse but that the level of coherence

between neighboring activities is keeping constant (Teece et al, 1994). Even though a

firm becomes more diverse by performing more new activities, its level of coherence

is maintained.

To summarize, TCE and RBV jointly provide the theoretical framework for issues of

vertical integration. TCE focuses on the firms’ trade-off between using outside market

resources and producing in-house, while RBV emphasizes firms’ unique capabilities

to create competitive advantage. According to TCE, firms become vertically

integrated due to the high transaction costs owing to high asset specificity and risk of

opportunism; whereas RBV explains that a firm’s decision of integrating new

activities is largely dependent on the relatedness of existing capabilities and the

capabilities required by performing new activities.

2.2 Industry Architectures

The concept of industry architecture literature examines the relationship between

firms and the industrial environment with regard to managerial strategy and the

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performance of firms. As firms grow and evolve under the economic environment,

they may also contribute to the shaping and changing of industry architecture.

In the traditional Bain/Mason industrial organization paradigm, industry structure was

defined as the relatively stable economic and technical dimensions of an industry that

provided the context in which competition occurred (Bain, 1972). It is suggested that

industry structure (the degree of seller and buyer concentration, product

differentiation, and barriers to entry) determines the behavior or conduct of firms,

whose joint conduct then determined the collective performance of the firms in the

marketplace (Bain, 1968; Porter, 1981). The underlying notion is that industry

structure determines the behavior of firms, and hence determines the firm

performance, which was known as the structure-conduct-performance view. Scholars

who are concerned with firm performance must be concerned with industry structure.

The limitation of traditional industry organization paradigm is that it gives full

priority to the importance of the outside economic environment, but neglecting the

firms’ capabilities to change the structure. Brusoni et al (2011) explain what drove

particular industry participants to change the vertical structure, showing how firms

transform their industry environment, as opposed to merely reinforcing it.

Traditionally, industry structure is identified as number and size distribution of firms

with regards to concentration and barriers to entry. Industries were understood in an

atomistic sense as “a group of sellers or of close-substitute outputs who supply a

common group of buyers.” In that sense, industry structure refers to the nature of

product markets in terms of the concentration of seller and buyer, product

differentiation and barriers to entry (Bain, 1968; Porter, 1981). Homogeneous sector,

consisting of firms undertake similar activities, is the primary unit of analysis for

industry structure in an atomistic sense. Since inter-firm relations are widely observed

among various industry groups and products are supplied by large networks of

manufacturers and service providers, attention should be paid to the heterogeneous

sector that comprises firms engaged in complementary activities. From this relational

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sense, industry structure is defined as the architecture of these relationships (Jacobides

et al., 2006).

Researchers who study industry architecture are interested in vertical integration and

vertical specialization. Jacobides (2005) provides an inductive theoretical framework

to explain how and why vertical disintegration happens, showing that transaction

costs are an incidental feature of industry evolution. He suggests that the real drivers

for vertical disintegration are benefits from specialization and potential gains from

trade. Jacobides and Winter (2005) argue that firms do not take their transactional

environment as given; rather they can operate on and change it. Transaction costs

theory does not address how industries or value chain structures evolve and does not

ask the question of whether firms can choose to make or buy (Jacobides, 2005).

Another work by Jacobides, Knudsen, and Augier (2006) qualifies Teece’s predication,

by positing that firm can create an “architectural advantage” in terms of high levels of

value appropriation without the need to engage in vertical integration and concludes

that firms can benefit from innovation by managing the industry’s architecture

carefully so they become the “bottlenecks” of their industry. Cacciatori and Jacobides

(2005) develop a framework to provide explanations that industries may shift to

vertical reintegration after long periods of vertical specialization. They observe that as

various groups shape and change the nature and boundaries of industries towards

vertical specialization, they create distinct knowledge bases in the industry.

Specialization of firms coupled with increasing distinct knowledge bases, firms in

such environment will suffer difficulties in coordination management across

boundaries and establishment of inter-firm relations. Reintegration is advanced by

firms seeking to protect their capabilities, through strategically changing their

institutional environment to create new all-in-one, integrated markets (Cacciatori &

Jacobides, 2006).

Besides vertical integration and disintegration, Jacobides and Billinger (2006)

examine permeable vertical architectures that are partly integrated and partly open to

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the markets along a firm’s value chain. They indicate that firms can make, buy, and

ally by enabling upstream units to sell to other manufacturers and downstream unites

to buy intermediate products from other firms in the same sector. The firm therefore

designs a “vertically permeable boundaries”.

Luo and Magee (2010) develop metrics and methods to measure the degree of

hierarchy in transactional relationships among firms in two large industrial sectors in

Japan: automotive and electronics. The findings indicate that there is an absence of

hierarchy in transaction networks within electronic sector, because firms in electronic

sector exhibit two characteristics: 1) they participate in multiple stages of industry

value chains and hence are vertically integrated, but also 2) they purchase inputs from

and sell products to other firms in the sector (Luo et al., 2012).

While firms often trade off economizing on transaction costs versus access to

dispersed knowledge stocks and enhanced flexibility in marketing these important

governance decisions, many firms are partially integrated and simultaneously

outsource some activities (Harrigan, 1984). These firms seek to identify the most

effective balance in bother organizing alternatives to leverage their benefits and

mitigate their costs (Rothaermel et al., 2006). This organizing approach is labeled as

taper integration, following Harrigan’s theoretical contribution that firms taper

integration “when firms are backward or forward integrated but rely on outsiders for a

portion of their suppliers or distribution” (Harrigan, 1984). Bonaccorsi and Giuri

(2001) develop the argument that the long term structural evolution of an industry

depends on the evolution of a vertically-related downstream industry. They claim that

the evolutionary dynamics of the downstream industry, in terms of number of firms

and products, entry, exit and concentration, is transmitted to the upstream via the

structure of the network of vertical exchange relations (Bonaccorsi & Giuri, 2001).

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2.3 Transactions

Transactions are the most basic form of inter-firm relationship and are a fundamental

unit of economic analysis (Williamson, 1975). Within a sector, transactions in

intermediate markets serve to link and coordinate complementary activities across

firms (Jacobides & Winter, 2005; Baldwin, 2008). Williamson (1985) defined a

transaction as “a transfer across a technologically separable interface”, though he did

not specifically explain what “technologically separable interface” is. To address the

question of why transactions occur in a particular place, Baldwin (2008) develops a

theory of location of transactions and the boundaries of firms in systems of production

(viewed as networks of tasks), drawing on modularity theory. Transactions are defined

as “mutually agreed-upon transfers with compensation, are located within the task

network and serve to divide one set of tasks from another” and are “designed to match

their locations” (Baldwin, 2008). Here, transaction is no longer the primary unit of

analysis and is more than a simple “transfer” indicated by Coase (1937) and

Williamson (1985), instead it is a “reciprocal exchange” (Baldwin, 2008) rooted in a

complex network structure.

Opportunistic transaction costs have been the focus of Williamson’s transaction costs

economics while Baldwin (2008) lays the emphasis on mundane transaction costs

which are defined as the “costs of defining, counting and compensating for things

transferred.” Specifically, opportunistic transaction costs plus mundane transaction

costs together equals to the total transaction costs. Drawing on modularity theory,

modules are loosely coupled at thin crossing points where transfers are fewer and less

complexity in comparison to transfers at thick crossing points within modules.

Therefore, placing transactions at module boundaries – thin crossing points –

generally achieve the lowest mundane transaction costs. When the network structure

is fixed and transactions are placed at thick crossing points, transaction designers

should make a tradeoff between mundane and opportunistic transaction costs to

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achieve an optimal transaction. Also, the task network structure can be changed

through the process of modularization to make a thick crossing point become thinner.

Modularizations create new module boundaries with relatively low transaction costs

and thus make transactions feasible where they were previously impossible or very

costly (Baldwin, 2008). And the new module boundaries (new locations of

transactions) enable new entry of firms and upgraded competition, contributing to

changes of industry structure. There exist transaction-free zones where transfers occur

without the burden of costs. Baldwin (2008) indicates that the thin crossing points

between transaction-free zones constitute “breakpoints” that firms and industries

become partitioned.

2.4 Global Value Chains

In business management, the concept of the value chain was first introduced by

Michael Porter (1985). Value chain explains how value flows and consists of activities

that create value. According to Porter’s theory, firms should create sustainable

competitive advantage in order to survive and thrive. To achieve competitive

advantage, firms should develop a superior value chain or at least a more advanced

one than their competitors. At the firm level, the value chain represents a set of

activities and processes that firms are involved in. Those activities and processes

provide values to final customers in the form of product or service. But Porter’s value

chain was a series of intra-firm activities and concerned with the value flowing within

a single firm.

The current interpretation of a value chain refers to a series of sequential and

sometimes parallel activities conducted by multiple firms with complementary

capabilities. At an industry level, value chain is a physical representation of sequential

processes from design to distribution - starting with raw materials to manufacturing

and ending with final products and services.

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The emergence of global value chains (GVCs) is a consequence of the global

integration of industries. A growing body of literature concerns the governance and

evolution of GVCs. GVCs can exhibit buyer-driven and producer-driven governance

patterns. Gereffi (2002) indicates that in the producer-driven GVCs, large

transnational manufacturers exert control over backward linkages with raw material

and subcomponent providers, and forward linkages into distribution and retailing. In

buyer-driven GVCs, large retailers, marketers and branded manufacturers play the

vital roles in setting up decentralized production networks (Gereffi, 2002). The

apparel industry is an example of buyer-driven global value chain. Three factors

determine the governance and transformation of global value chains: 1) the

complexity of transactions; 2) the ability to codify transactions; and 3) the capabilities

in the supply-base (Gereffi et al., 2005).The concept of GVCs contributes to

understanding three features of a particular industry or group of industries: 1) the

geography and character of linkages between tasks in the chain of value added

activities; 2) power distribution among firms in the chain; and 3) the role that

institutions play in structuring business relationships and industrial location (Sturgeon

et al., 2008).

Gereffi, Humphrey, and Sturgeon (2005) identify five basic types of value chain

governance as follows: market, modular, relational, captive and hierarchical

characterized by vertical integration. And their work indicate that apparel industry has

shifted from a captive value chain to a more complex relational value chain, and such

migration is mainly driven by increasing supplier competence. This notion is

consistent with findings from other studies that there has been a shift among apparel

suppliers in developing countries from providing basic assembly to offering more

flexible and efficient services, such as full-package production and lean or agile

manufacturing (Abernathy et al.,2000, 2006; Gereffi, 2001).

Imagine a simplest value chain raging from raw material suppliers, to manufacturers,

to product distributors and service providers, where each stage is associated with

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higher value-added than its former stage. Conventional wisdom suggests that firms

who want to capture the most value, the best strategy is to position downstream in the

value chain and by the same token, countries who want to achieve economic

prosperity should encourage national firms to occupy the downstream positions and

leave the less value-added upstream positions to less developed countries. In the

United States, manufacturing sector has been offshore to less developed countries in

response to trends in creating and sustaining comparative advantage and efforts to

gain economic superiority on a global scale by capturing the downstream positions in

global value chains. However, there is skeptical view on the dominant growth strategy,

for instance, Tassey (2010) points out that United States has let the manufacturing

sector languish. The plight of the manufacturing sector is not only an “industry”

problem but also a “value chain” issue. He argues that the policy of prospering by

specializing in services ignores both the co-location synergies with manufacturing and

the fact that other economies are aggressively integrating forward into high-tech

services (Tassey, 2010).

In conclusion, global value chains capture value-flowing in the global economy. With

a thorough understanding of the direction of value flows, firms, organizations and

countries would tend to develop strategic polices to govern and adapt the value chains

for their advantage.

2.5 Industry Classification

Industry classification is an important criterion for researchers who aim to analyze

industry architecture. The works on identifying and investigating industry

architectures will be much easier if a standard industry classification is shared. Such

classification schemes as the US-based Standard Industrial Classification (SIC) and

North American Industry Classification systems have been introduced for a long time

and updated periodically. NAICS was developed under the auspices of the Office of

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Management and Budget (OMB), and adopted in 1997 to replace the Standard

Industrial Classification (SIC) system (U.S. Census Bureau). However, studies on

industry classification have questioned the reliability and capability of those schemes

to correctly reflect industry architectures since those industry classification systems

have not changed correspondingly to the increasing complexity of industry activities.

Hicks (2011) examines the relationship of structural change in the economy and

industrial classification and indicates that the understanding of structural change is

compromised because scholars do not clearly articulate the limit of the classification

infrastructure that shapes empirical analysis. Dalziel (2007) proposes an alternative

systems-based approach to classification, taking the view that understanding industry

structure is not understanding competition among firms that conduct similar activities,

but understanding cooperation among firms that undertake complementary activities.

Dalziel (2007) distinguishes the traditional and current views of industry architecture

as “atomistic” and “relational”.

The conceptual foundations of firm classification schemes have two dimensions:

supply/demand orientation and structural assumption (Hicks, 2011). The supply

orientation shows a production basis while the demand orientation indicates a market

basis. From supply/production orientation, firms are grouped into a particular industry

based on the similarity of their production activities and processes. Meaures of

inter-industry relatedness capture the similarity of firm activities and resources. Bryce

and Winter (2009) developed a general inter-industry relatedness index that

contributes to empirical assessments that reply upon the concept of relatedness

between resources to characterize the direction of growth of the firms. Such a

relatedness index provides economic rationale for a firm participating in industry A to

perform and integrate activities of industry B. Whereas from demand/market

orientation, firms are clustered into an industry based on the complementarities of

their production processes and activities engaged in. In a production orientation, an

industry is a group of business establishments supplying similar outputs in the form of

product or service, and performing similar production activities; while in a market

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orientation, an industry is a group of business establishments producing close

substitutes and involved in complementary activities.

The current dominant industry classification systems (e.g. NAICS) are from a supply

orientation and the underlying criterion for grouping is “similarity”. Building on the

“similarity” criterion, for example, apparel manufacturers are grouped in one industry

in that they are engaged in apparel-making activities, and the complementary firms

who supply textiles, sewing machines, information systems, transportation and

logistics services, and marketing and branding are grouped into other industries

because those firms are involved in different sets of activities. However, from a macro

level, all those firms collectively address consumer’s demand for clothing even

though they undertake different sets of activities.

There are three limitations of the traditional activities-based approach. First, they fail

to reflect industry structure. Specifically, they fail to provide indication of

relationships between firms since “the firms classified in a given category are no more

likely to have relationships with the firms in the neighboring categories, than they are

to have relationships with firms in other sectors” (Dalziel, 2007). Second, they group

firms that serve similar purposes/demands into different industries simply by

identifying their production activities. Dalziel (2007) suggests that competitors may

employ different technologies and conduct different activities to meet similar

demands, but they do not serve for fundamentally different demands. It should be

noted that supply-based systems may group firms that supply very different demands

together, but a demand-based systems may group firms that perform very different

activities together. Finally, the boundaries between manufacturers and service

providers have become blurred as a result of technological innovation. Since most

industries are doing business with the support of computer and information

technology, it is hard to distinguish the role of an IT firm between manufacturer and

service provider by just considering their production activities. The question of

industry classification is not so much how to group similar firms into industries but

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how to group industries into sectors in a meaningful way.

Dalziel (2007) proposed a system-based approach to industry classification that takes

demand as the primary organizing principle, and the sector as the primary unit of

analysis, as opposed to the activities-based approach. She shifted the traditional focus

on ‘activities’ conducted by firms to ‘demand’ that multiple firms collectively respond

to and provided an application in communication equipment subsector to show that

the systems-based approach perform better reflects the industry structure and

inter-firm relations than the traditional North American Industry Classification system.

Dalziel (2007) points out that as a variety of complementary firms work together to

collectively address similar fundamental demands, the classification system’s unit of

analysis must accommodate firms that are different from one another, both in terms of

the nature of the specific demand to which they individually respond, and in terms of

the activities they undertake. This notion calls attention to the vertical sector that start

with fundamental demands, sequenced by interdependent layers of industries

collectively addressing the demands. The principle of the systems-based approach lies

in the dependency relationships. This means that final customers depend on service

providing firms to fulfill their needs and by the same token, service providers depend

on other complementary firms to supply input products/services. This hierarchical

dependency structure is consistent with the architecture of global value chain.

To summarize, the supply-oriented classification systems fail to consider the purpose

for which firms conduct activities and to whom and from whom they sell and buy

products/services. In addition, activity-based classification may blur the inter-firm

relations and isolate individual firms from the “network” by simply focusing on their

production activities. The conventional industry classification systems fail to capture

the division of labor and the network of firms. Industry structure has changed

correspondingly with the dense network of inter-firm relations, hence, industry

classification systems should change accordingly for the purpose to provide a holistic

view of economy for researchers and policy makers. Suggestions are given as follows:

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1) considering heterogeneous sector rather than homogeneous industry as the primary

unit of analysis; 2) focusing on cooperation and complementarity rather than

competition and similarity among multiple firms; 3) taking a demand view to

understand the hierarchical dependency relationship of firms.

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3. Theoretical Development

My theory is based on two concepts: inter-firm similarity and inter-firm

complementarity. In Section 3.1, I introduce these two concepts, and in Section 3.2, I

develop my hypotheses regarding the determinants of major inter-firm relations, and

evolution of the apparel sector over time.

3.1 Theory

Richardson (1972) considers industry as carrying out a large number of activities that

need to be carried out by firms with appropriate capabilities. He distinguished

activities as similar versus complementary. Activities that require the same capability

for undertaking are called similar activities while activities are complementary when

they represent different phases of a process of production and require coordination

(Richardson, 1972). The concept of inter-industry similarity mainly addresses the

“distance” between two industries (that the firms belong to) by calculating their

similarities (Teece et al., 1994; Bryce & Winter, 2009). The notion of inter-firm

complementarity refers to the inter-industry dependencies as indicated by input-output

tables, or as indicated by firms’ sector roles. In this study, inter-firm relatedness is

operationalized as the NAICS proximity, while inter-firm complementarity is

operationalized as the firms’ sector roles dependency (Dalziel, 2007).

3.1.1 Similarity

Several researchers have studied the degree to which firms’ engage in similar or

related activities. Especially for multi-product firms, they are active in many

industries that share common characteristics regarding production technologies

(Neffke & Henning, 2008). According to the prevalent industry classification systems

(e.g.NAICS), firms that perform similar activities are classified in the same industry.

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The knowledge about similarity between industries is important to understand

economic transformation, firm growth and diversification, and firm performance

(Penrose, 1959; Rumelt, 1974). Given the importance of similarity or relatedness

between industries, research from strategic management area has developed different

measures to capture the degree of inter-industry relatedness between firms in different

industries.

Rumelt (1974) captures the concept of relatedness in his study on firm diversification.

Four broad categories of firm diversification are identified as single product firm,

dominant product firm, related product firm, and unrelated product firm. Three ratios

are used for classification as follows: 1) the specialization ratio which is defined as

the proportion of a firm’s revenues that is attributable to its largest discrete

product-market activity; 2) the related ration which is defined as the proportion of its

revenues that are attributable to the largest group of businesses that are related in

some way to one another; 3) the vertical ratio which is defined as the proportion of a

firm’s revenues attributable to all of the by-products, intermediate products, and final

products of a vertically integrated sequence of manufacturing operations (Rumelt,

1974). However, this procedure measures relatedness on a nominal level, only

allowing comparisons within group averages (Lien & Klein, 2009).

The majority of studies has been focused on firm diversification, but much less has

been directly emphasized on inter-industry relatedness. Recently, researchers have

constructed inter-industry relatedness indices based on the frequency with which pairs

of industries appear jointly in firm portfolios (Teece et al., 1994), technological

relatedness as measured by the technologically related of products produced by

different plants in Sweden (Neffke & Henning, 2008), or the joint industry

participation decisions of U.S. manufacturing firms (Bryce & Winter, 2009). Teece et

al (1994) develop a corporate coherence measurement to explain the similarities and

differences in the nature of coherence across firms and industries, drawing on the

survivor principle. They assume that “activities which are more related will be more

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frequently combined within the same corporation”. Teece et al. (1994) count the

frequency of joint occurrences of pairs of industries in firm portfolio and standardize

this frequency to identify linkages between pairs of industries that exceed the

expected random assignments of industries. Following Teece et al.(1994), Bryce and

Winter (2009) upgrade the measurement and develop a general inter-industry

relatedness index which is a useful tool for assessing inter-industry relatedness in any

context requiring such measure (Bryce & Winter, 2009).They infer inter-industry

relatedness from the aggregate activity combinations of firms from both supply side

and demand side and such approach provides a strong resource-based measure of

relatedness because it reflects the unobservable ways that firms share resource among

industry activities (Bryce & Winter, 2009). However, the major limitation is that the

general relatedness index is currently computed only for manufacturing industries. It

is not applicable for studies that investigate industries from service provider sectors.

Neffke and Henning (2008) measure technological relatedness from a production

perspective between industries based on the dataset of products produced in plants in

all manufacturing industries in Sweden. However, they did not provide any real

quality assessment of their relatedness measure and their measure is also only for

manufacturing industries.

Relatedness based on SIC system is easily available. The 2-, 3-, and 4-digit levels of

SIC system are used as points on an underlying scale of relatedness, and arithmetic

values are assigned to the distances (Lien & Klein, 2009). However, the SIC-based

measures rely on the assumption that industries are homogeneous within category

levels which can be problematic when the breadth of the industry classifications

varies (Robins & Wiersema, 2003). More importantly, the SIC-based measurement

does not consistently reflect relationships among valuable resources in the ways that

firms actually combine them to create value (Bryce & Winter, 2009).

In general, the different measures can be classified into three categories: categorical

measures, RBV-based measures with regard to survivor principle, and SIC-based

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measures. All of the studies that consider inter-industry relatedness employ similarity

in firm activities as their relatedness criterion.

3.1.2 Complementarity

There is a growing body of research that considers the importance of complementarity

in the firms’ knowledge resources and production activities. The landmark article of

Teece (1986) introduces the concept of “complementary assets” to explain the failure

of innovating firms to take the lion’s share of profitability. To successfully

commercialize an innovation, besides core technical know-how, there is need for

complementary capabilities. Such complementary requisites include services such as

distribution, marketing and branding, competitive manufacturing and after-sales

customer services. It is demonstrated that when imitation is easy, the significant

economic returns may accrue to the owners of such complementary assets, instead of

the innovators (Teece, 1986). Aspiring to extend Teece’s framework, Jacobides,

Knudsen, and Augier (2006) investigate how innovating firms can benefit from value

creation and appropriation with a focus on industry architectures, by treating

complementarity and mobility as two distinct components of co-specialization. The

study suggests that firms can strategically reshape the architecture of their sector by

encouraging competitions in complementary activities and restricting mobility and

competitions in their own segment (Jacobides et al., 2006).

A wide range of studies examine the inter-firm alliance formations and firm

performance with regard to complementarity. Arora and Gambardella (1990)

investigate the complementarities among strategies of external linkage of the large

biotechnology firms with different parties (e.g. universities, small/medium sized

research-intensive firms). They further indicate that the locus of innovation should be

a “network” of inter-organizational relations. Rothaermel (2001) focuses on the

inter-firm cooperation between incumbents and new entrants when the incumbents

have complementary assets within their firm boundaries that are critical to

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commercialization. His study shows that, at the industry-level, incumbents exhibit a

preference towards alliances that leverage complementary assets over alliances that

focus on building new technological competencies. A study by Lin, Yang, and Arya

(2009) investigates firm performance as a consequence of firms’ alliance partner

selections. Combining the RBV and institutional perspectives, this study explores the

interactions of resource complementarity and institutional associations between the

firm and its alliance partners and demonstrates that having alliance partners with high

resource complementarities will boost firm performance.

Complementarity of firms’ knowledge resources is also crucial to firm performance.

Studies have investigated the impact of cross-business knowledge synergies in terms

of relatedness and complementarity on performance of multi-business firms. The

results indicate that synergies from product, customer, or managerial knowledge

relatedness do not improve firm performance, while synergies arising from the

complementarity of the three aforementioned types of knowledge relatedness

significantly improve both marked-based and accounting-based performance of the

multi-business firms (Tanriverdi &Venkatraman, 2005).

The aforementioned studies have operationalized complementarity in terms of firm

resources (e.g. knowledge resources, tangible assets, and R&D capabilities) to predict

firm performance and profitability, inter-firm alliances, and firms’ decisions on

vertical integration. In my study, complementarity is operationalized as the degree of

dependency of firms’ different sector roles to predict the likelihood of inter-firm

transactions.

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-Firm diversification in terms of

product relatedness to explain the

performance differences of firms

(Rumelt, 1974, 1982)

-Coherence to explain firms’ growth

(Teece et al., 1994)

-Technological relatedness to

explain the composition and change

of a regions portfolio of

manufacturing industries (Neffke &

Henning, 2008)

- Relatedness index to predict entry

mode (Bryce & Winter, 2009)

-Complementary assets to

successfully commercialize an

innovation (Teece, 1986)

-Complementarities among

strategies of external linkage of

firms (Arora & Gambardella, 1990)

-Complementarities in terms of

firms’ knowledge resources

(Tanriverdi & Venkatraman, 2005)

- Predicting inter-firm relations in

the same industry (Schilling &

Steensma, 2001)

-Survivor-based relatedness to

predict firms’ decisions to enter new

markets (Lien & Klein, 2009)

-Incumbents prefer alliances that

leverage complementary assets

(Rothaermel, 2001)

-Encouraging competitions in

complementary activities can help

firms reshape the sector architecture

(Jacobides et al., 2006)

-Having alliance partners with high

resource complementarities will

boost firm performance (Lin et al.,

2009)

Figure 3.1 Quadrant for Similarity, Complementarity, Intra-firm and Inter-firm

Relations

3.2 Hypothesis Development

In the following part, I derive hypotheses for the major inter-firm transactions. The

hypotheses focus on the significance of inter-firm similarity and inter-firm

complementarity in predicting the existence and magnitude of a major transaction

between firms. In addition, I provide evidence on the nature and evolution of the U.S.

apparel sector on a macro level.

Complementarity Similarity

Intra-firm

Inter-firm

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3.2.1 The Determinants of Major Inter-firm Transactions

Inter-firm Relatedness

Industries are comprised of groups of similar firms; therefore, inter-firm relatedness is

the relatedness of pairs of industries that firms belong to. One of the core concepts of

corporate strategy is inter-industry relatedness, which is considered important to

explain the performance differences of firms in terms of profitability (Rumelt, 1982),

to determine the direction of firm growth and diversification (Rumelt, 1974; Teece et

al., 1994), and to predict firms’ decisions to enter new markets (Lien & Klein, 2009).

Inter-industry relatedness takes “similarity” as the criterion for identifying major

inter-firm relations.

A large volume of studies have investigated the effects of inter-industry relatedness on

firm diversification, growth, entry mode, organizational choice, and acquisition and

merger performance. To show the relationship between diversification strategy and

firm profitability, Rumelt (1982) introduced categorical degree of relatedness to

capture the product diversity. He finds that the highest levels of profitability were

exhibited by firms diversifying primarily into related areas that share common core

skill and resources with current production activities. Bryce and Winter (2009) predict

the mode of entry of an expanding firm and find that the relatedness index is

significant in predicting the choice between acquisition and organic expansion. Neffke

and Henning (2008) measure technological relatedness between manufacturing

industries in Sweden and indicate that relatedness has significant explanatory power

for the composition and change of a regions portfolio of manufacturing industries.

Lien and Klein (2009) construct a survivor-based measure of inter-industry

relatedness to predict firms’ decisions to enter new markets.

Transaction costs economics provides theories on firms’ make or buy decision and

views the governance decision as dichotomous (Williamson, 1985). Another strand of

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literature indicates that the choice for firms to integrate or to transact is not binary.

Parmigiani (2007) examines firms’ decision on simultaneously make and buy the

same good, instead of solely making or solely buying. Firms will employ concurrent

sourcing strategy because they desire to simultaneously monitor suppliers, produce

efficiently, and improve processes (Parmigiani, 2007). Recent studies (Parmigiani,

2007; Parmigiani & Mitchell, 2009) examine the concurrent sourcing strategy

employed by firms and suggest that concurrent sourcing resolves the coordination

versus flexibility quandary. Jacobides and Billinger (2006) introduces the concept of

“permeable vertical architectures” that are partly integrated and partly open to the

markets along a firm’s value chain, and such architectures enable firms to

concurrently use both internal and external suppliers and customers. Permeable

boundaries allow firms to selectively participate at multiple points along the value

chain (Jacobides & Billinger, 2006), and therefore engaging in tapered integration

(Harrigan, 1985). The concurrent sourcing strategy and the design of vertically

permeable boundaries relieve the tension between the traditional make-and-buy view

and modularity theory. Modularity theory predicts that firms tend to outsource

complementary activities to achieve flexibility (Sanchez & Mahoney, 1996; Baldwin

& Clark, 2000; Brusoni et al., 2001).

Several studies expect inter-firm relations between firms in the same industry, that is

to say, in the firms that undertake same activities. Schilling and Steensma (2001)

investigated three primary ways for firms to substitute tightly integrated activities

with loosely coupling activities and they are contract manufacturing, alternative work

arrangements, and alliances, with the purpose to test the significance of several forces

that drive the use of modular organization forms. The main argument for their study is

that there is a positive relationship between heterogeneity in the production process

(inputs and demands) for an industry and the use of flexible modular forms. However,

all their hypotheses are only partially supported, indicating either theoretical or

empirical difficulties. I believe the difficulties can be empirical because firms may be

less likely to contract and ally with firms in the same industry than with firms in other

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industries. Tomlinson (2010) investigates relationship between inter-firm cooperative

ties and innovation in five UK manufacturing industries. This paper finds out that

vertical cooperative ties are significant in explaining firms’ level innovation

performance while horizontal cooperation between firms (i.e. cooperative with

competitors) does not appear to be significant in explaining innovation. Another study

by Lamprinopoulon and Tregear (2010) focuses on the inter-firm relations in small

and medium sized firm (SMEs) and explores the links with marketing performance.

The findings of their analysis suggest that the configuration of horizontal relationships

between producer SMEs has little bearing on marketing performance, unless

accompanies by strong vertical connections between key members of the SME cluster

and other actors in the supply chain. Therefore, I expect that transactions take place

between firms in the related industries, not between firms within the same industry.

Accordingly, I propose that a major inter-firm transaction is associated with inter-firm

similarity. But I expect an inverted-U relationship between inter-firm similarity and

major inter-firm transaction. Firms are more likely to transact with firms from similar

or related industries, but will be less likely to transact with firms from unrelated

industries where there is no supply-demand relationship or with firms from the same

industry where there is more competition than cooperation.

Hypothesis 1:

There is an inverted-U relationship between inter-firm similarity and the existence and

magnitude of major inter-firm transaction.

Inter-firm Complementarity

Even though “complementarity” was widely examined by studies in the areas of firm

boundaries, profitability of innovators, industry architectures, strategic alliances, and

firm performance, there is no applicable measure of complementarity. For inter-firm

complementarity, it is difficult to systematically identify complementarity and even in

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vertical value chain, there is absence of general means of identification.

One approach to identify the inter-firm complementarity is to use Input-Output (I-O)

tables. I-O analysis was first proposed by the Nobel Prize laureate Wassily Leontief

and describes inter-industry transactions as a proportion of total industry inputs and

outputs. I-O analysis tracks the interdependence among various producing and

consuming sectors of an economy (BEA, 2012). Input-Output tables indicate

inter-industry and therefore inter-firm complementarity. The bigger the proportion of

industry i’s input that is procured from industry j, the more likely that there will be a

buy-sell relations between firms in industry i and j. However, the I-O tables are not

sufficiently fine-grained to indicate the likelihood of inter-firm transactions across all

industries. In addition, the I-O tables are produced infrequently and usually with a lag

of thirty months for national tables, failing to keep up with the recent trends in several

industries and the changing economy.

Another approach is to use the concept of “sector role” in value chain and

operationalize complementarity as firms’ sector role dependencies (Dalziel, 2007).

From a demand perspective, there exist dependency relations between sector roles.

For instance, as service providers depend on manufacturers to provide inputs, by the

same token, manufacturers depend on material providers to supply materials. Sector

roles are defined on the basis of complementarity in activities. Within the vertical

structure of value chain, inter-firm relations will be hierarchically ordered from firms

providing services to final customers at the highest level, firms manufacturing

products at intermediate level, and firms supplying raw materials at the lowest level.

Consistent with the structure of global value chains, sector roles are ordered from

upstream sellers to downstream buyers. Dalziel (2007) proposed a theory-based

approach to identify the most important inter-industry complementarity. Her concept

of sector role is based on the modularity theory (Baldwin & Clark, 2000) that

identifies two sector roles – systems integrator and component supplier. She identifies

sector roles and distinguishes between service and manufacturing subsectors and

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between central firms and complementary firms.

Previous studies have investigated the impact of a firm’s sector role on firm

performance and profitability. Sector role is important to explain why firms in the

same sector may experience the same environmental conditions differently (Dalziel &

Zhang, 2010). Accordingly, I propose that the existence and magnitude of a major

transaction between two firms is positively associated with their inter-firm

complementarity (dependency relation between sector roles).

Hypothesis 2:

There is a positive relationship between inter-firm complementarity and the existence

and magnitude of major inter-firm transaction.

3.2.2 The Evolution of the Apparel Sector

Recent studies have described inter-firm network structure and tried to explore

variation in network structure across industries. Rosenkopf and Schilling (2007)

compare alliance networks in 32 industries and demonstrate substantial differences in

network structures. They identify three types of networks: 1) disconnected with low

connections; 2) spider-webs with a high level of connections; and 3) hybrids with a

moderate level of connections. They further explain this variation by referring to

technological uncertainty and dynamism, product modularity and architectural control

that characterize the industries. Luo (2009) measures the degree of hierarchy of

transaction networks among firms in Japanese automotive and electronics sectors and

the empirical results show that the electronics sector exhibits a significantly lower

degree of hierarchy than the automotive sector, due to the presence of many

transaction cycles. It is worth reporting that the cycles in the electronics industry

disappear if the largest firms are taken out of the sample.

Since my data contains information at an industry level and the NAICS codes enable

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me to identify the four apparel sector roles1, I expect to provide evidence on structure

of the U.S. apparel sector on a macro level. My first assumption is that there will be a

shrinking proportion of manufacturer firms involved in transactions in the U.S.

apparel sector. This expectation is consistent with Tassey’s (2010) view that the U.S.

outsources and offshores its manufacturing activities to less-developed countries

because U.S. firms are more willing to capture the downstream positions that take the

most value-added to gain economic superiority. The second expectation is that there

will be an increase in the diversification of multiple players that serve as external

firms from non-apparel industries and undertake complementary activities to apparel

firms, because nowadays products and services are provided by networks of firms.

Abernathy et al (1995) provide empirical results that apparel supplier have made

increasingly investment in information technologies, distribution systems, and other

associated services.

Hypothesis 3:

Over time, there will be a shrinking proportion of manufacturing firms relative to

service providers involved in major transactions in the U.S. apparel sector.

Hypothesis 4:

Over time, the proportion of major transactions that involve firms outside the apparel

sector will increase.

Luo and Magee (2011) present a metric and technique to quantitatively assess the

extent to which self-organizing directed networks exhibit a flow hierarchy. In the

appendix, they differentiate all the links of a network into four different types:

1) Regular: the link connects from anode on a pre-defined low level (i) to a node on

its adjacent higher level (i-1)

2) Level-Skipping: the link connects from a node on a pre-defined lower level (i) to a

node on a level (j) higher than its adjacent higher level (i-1), i.e. j < i-1; 1 Apparel sector roles comprise of Textile provider, Apparel manufacturer, Wholesaler, and Retailer.

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3) In-layer: the link connects between nodes on the same level (i)

4) Backward: the link connects from a node on a predefined high level (i) to a node

on a lower level (j), i.e. i < j

Following Luo and Magee (2011), I classify the transactions in the apparel industry

into four types: 1) Regular (one-level up), 2) Level-skipping, 3) Same-level, and 4)

Backward. My expectation is that regular transactions will be more likely to occur

than the other types of transaction. For example, within the apparel sector, a

preponderance of links will be found between textile providers and apparel

manufacturers or between apparel manufacturers and retailers while relatively less

links will be found between textile providers and retailers. The directions of links are

expected to be consistent with the value flows in global value chains. The majority of

links will start from upstream sector roles and travel to downstream sector roles.

However, there can be backward links and cycles because of the existence of

vertically and tapered integrated firms and the fact that firms develop permeable

boundaries and employ concurrently sourcing strategy. While vertical disintegration

may be the long-term trend; over short time periods both the bicycle components

industry (Fixson & Park, 2008), and the British building industry (Cacciatori &

Jacobides, 2005) experienced vertical re-integration as a consequence of strategic

choices made by firms. Firms are partially integrated and concurrently sourcing in

order to achieve the most effective balance in both organizing alternatives to leverage

benefits and mitigate costs (Rothaermel et al., 2006). Harrigan (1984) defines this

organizing approach as taper integration that firms are backward or forward integrated

but also relying on outsiders for a portion of their supplies or distribution. Jacobides

and Billinger (2006) conducted a longitudinal study of a major European apparel

manufacturer and documented its redesign into permeable vertical architecture that

allows firm units to both make and buy, and transfer downstream or sell. It is

indicated that increased permeability enables more effective use of resources and

capacities, better matching of capabilities with market needs, and benchmarking to

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improve efficiency (Jacobides & Billinger, 2006).

Hypothesis 5:

Over time, the proportion of the level-skipping, same-level and backward transactions

relative to transactions between vertically related pairs of industries will increase.

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4. Methodology

In this section, I first provide information about my data and identify my study sample to

test hypotheses. In the following part, I introduce my analytic approaches and measures

of dependent variables, independent variables and control variables. The last part

presents the results of descriptive statistics.

4.1 Data

I am fortunate to have access to a dataset of over 60,000 observations of major

transactional relations in the U.S. from 1976 to 2010. Cohen and Frazzini (2008) have

used this dataset for their award-winning research in finance area to explore the

customers’ impact on suppliers. Hertzel et al (2008) also use this dataset to study

bankruptcy spillover effects on the stock prices of customers, suppliers, and strategic

alliance partners. Even though this dataset provides a holistic view of transaction

networks over time, it has not been used to investigate the transaction networks’ structure.

The data depends on the fact that the U.S. Securities and Exchange Commission requires

firms (including foreign firms) that are publicly traded in the U.S. to report the

percentage of their revenues that is attributable to sales to a specific customer, in case

where those sales exceed 10% of total revenues.

4.1.1 Data Preparation

The data preparation consists of two major tasks: 1) Standardizing company names, and

2) Identifying customer industry NACIS codes. The seller names are identified, so the

task of standardization is to standardize the buyer names. The first criterion is to remove

observations where the customer types are not “company” and where customer (buyer)

names are incomplete. Because firms report their buyer names by various formats such as

a full name, a full name plus Corp, or an abbreviation, a same company can be identified

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by different company names. Therefore, with the help of a fuzzy string name-matching

algorithm to compare names, firm names with different reporting formats are identified

as the same firm in the whole dataset. The second task is to identify the missing NAICS

codes for buyers. The first step is to identify the unique buyer names and then to connect

those unique firm names with the dataset of Research Insight to find the corresponding

NAICS codes.

The result dataset includes 61,036 data records with gvkey codes for sellers, seller names,

NAICS codes for sellers, customer identifiers, unique identifier for buyers, buyer names,

NAICS codes for buyers, company type, geographic area code, geographic area type,

annual sales, segment identifiers, segment type, and reporting date of data records.

4.1.2 Data of Apparel Sector

Since my main interest lies in the apparel sector, I filter the data from the original dataset

that contains 61,036 data records. Each record is one row, presenting information (e.g.

name, NAICS Code) on a given seller, the corresponding buyer, and the transaction that

links the two. Of my research interest, data are extracted only from the apparel and

apparel-related industries. Therefore, based on North American Industry Classification

System (NAICS), I identify subsectors as follows: 313 (Textile Mills), 315 (Apparel

Manufacturing), 316 (Leather and Allied Product Manufacturing), 4243 (Apparel, Piece

Goods, and Notions Merchant Wholesalers) and 448 (Clothing and Clothing Accessories

Stores), and identify observations where either the seller or the buyer operates in areas of

the above selected subsectors. Same as my approach, Baldwin and Clark (2000)

identified new emerging sub-industries based on the SIC 4-digit codes to investigate the

changing structure of the computer sector.

As a result, the newly-extracted apparel industry dataset contains 2431 unique

observations in total from 1976 to 2010. Through filtering the “firm names” column, we

identify 277 different sellers and 135 different buyers. In case that there are overlapping

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firms appearing in both sellers and buyers, we identify 381 unique firms while there are

31 firms serving as both a seller and a buyer.

As the above-mentioned dataset is only about the inter-firm transaction relationships,

further data is expected to indicate firm attributes. I extracted the data about firm

revenues from Research Insight using the unique firm names. The new dataset is about

3142 records of firm information from 1992 to 2010 and the earliest data records in

Research Insight started from 1992. I fail to find all the unique firms identified from the

original apparel dataset because some firms may be acquired or closed before the year

1992, resulting the missing and changing of firm names in the dataset of Research Insight

software. Totally, there are 289 unique firms in the dataset of firm information while the

total unique firms identified from my original apparel dataset are 381. Figure 4.1 shows

the number of unique firms having information about revenues from 1992 to 2010. It is

worth mentioning that there are different firms for each year and it is rarely possible for a

particular firm appearing for the whole period.

Figure 4.1 Number of Unique Firms with Revenues

4.1.3 Apparel Sector Roles

I identify four major sector roles within the apparel sector: 1) Textile provider, 2) Apparel

manufacturer, 3) Wholesaler, and 4) Retailer. For sector roles, there is a “dependency”

158

217 207 212 225 219

206 196 186 177 164 157

145 131 120 113 107 102 98

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(Dalziel, 2007) pattern that retailers depend on wholesaler to supply inputs, wholesalers

depend on apparel manufacturers to provide inputs, and apparel manufacturers rely on

the textile providers to offer inputs. From a demand perspective, firms are positioned by

the relation of dependency.

In an industry level and based on the NAICS codes (4-digit level), textile provider

includes business establishments from industry groups of 3131, 3132, 3133, and 3141;

apparel manufacturer contains business establishments from industry groups of 3151,

3152, 3162, and 3169; the wholesaler is the industry group of 4243; and the retailer

contains business establishments from industry groups of 4481, 4482, 4483, 4511, 4521,

4529, and 4541. Other left firms that undertake facilitating activities are categorized as

external roles and they are from non-apparel sectors. External firms from other sectors

(e.g. lessors of real estate, electronics and appliance stores) facilitate the operation of the

apparel sector, but they are not necessary for the apparel sector. In Table 4.1 below, I

present the classification of NAICS (4-digit level) industry groups in the apparel sector

according to their sector roles. Table 4.2 provides the information for non-apparel

industries that appear more than 20 times.

Table 4.1 Central Roles in Apparel Sector

Apparel sector roles (Associated with 4-digit NAICS codes)

Textile provider

3131:Fiber, Yarn, and Thread Mills

3132: Fabric Mills

3133: Textile and Fabric Finishing and Fabric Coating Mills

3141: Textile Furnishing Mills

Apparel manufacturer

3151:Apparel Knitting Mills

3152:Cut &Sew Apparel Manufacturing

3162:Footwear Manufacturing

3169:Other Leather and Allied Product Manufacturing

Wholesaler

4243: Apparel, Piece Goods, and Notions Merchant Wholesalers

Retailer

4481:Clothing Stores

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4482:Shoe Stores

4483:Jewelry, Luggage, and Leather Goods Stores

4521: Department Stores

4529: Other General Merchandise Stores

4541: Electronic Shopping and Mail-Order Houses

Table 4.2 External Roles with Frequencies of Appearance over 20

External roles Frequency

3256: Soap, Cleaning Compound, and Toilet Preparation Manufacturing 25

3342: Communications Equipment Manufacturing 23

3361: Motor Vehicle Manufacturing 34

3399: Other Miscellaneous Manufacturing 26

4461: Health and Personal Care Stores 21

4511: Sporting Goods, Hobby, and Musical Instrument Stores 39

5311: Lessors of Real Estate 87

5416: Management, Scientific, and Technical Consulting Services 21

The external roles exist due to the fact that firms in the apparel sector have transactions

with firms from external sectors (e.g., Lessors of real estate, and Electronics and

appliance stores). The justification for identifying sector roles and external roles can be

explained that a complete structure of the apparel sector cannot be outlined by only

looking at groups of business establishments within the apparel sector especially when

the boundary between different industries is becoming blurry and the vertical cooperation

among complementary firms is overwhelmingly intense.

4.1.4 Transactional Networks in Apparel Sector

To have a better understanding of the transactional (buy-sell) relations in apparel sector, I

present graph visualizations created by Netdraw to show the transactional networks of

sellers and corresponding buyers. A graph presenting the information among relations

can efficiently provide visual evidence on the overall structure of networks. Netdraw is a

visualization tool from the social network analysis software package UCINET and it

allows graphic representation of networks including relations and attributes. Network

analysis uses graphic display that consists of nodes to represent actors and lines to

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represent ties or relations (Borgatti, Everett, & Freeman, 2002). Each node has a set of

attributes and each tie can be directed by the arrow. Coloring the nodes by attributes is a

powerful way of exploring general patterns of network.

To construct my transactional network, I use nodes to represent unique firms involved in

major transactions in apparel sector and lines to represent the existence of a transactional

relation. The direction of a buy-sell relation is shown by the arrow. According to value

chains, firms are ordered from textile providers, manufacturers, wholesalers, to retailers

from upstream to downstream. I create a single node named “universal customer” and

create ties that link retailers to this “universal customer”. By doing so, all retailers will be

positioned near the center. I also include the transactional relations between external

firms2 (non-apparel firms) and apparel firms. In the following, I show the graph

visualizations of transactional network identified by node attributes, namely, NAICS

code (2-digit and 3-digit) and sector role. Different NACIS codes and different sector

roles are distinguished by the unique colors as presented in graphs.

Figure 4.2 shows the transactional network indentified by the node attribute: NAICS

code (3-digit). The dark pink in the center is the universal customer that connected with

all retailers. Overall, nodes by different colors are sparsely scattered. The color with the

most frequency of appearance is the sandwash pink that represents NAICS code 315,

reporting that the majority of apparel firms involved in major transactions are from

NAICS subsector 315 (apparel manufacturing). Besides, it is difficult to visually identify

any particular patterns of interest from the messy graph.

2 External firms are from non-apparel industries but are involved in transactions in apparel sector.

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Figure 4.2 Transactional Network by NAICS Code (3-digit)

Figure 4.3 shows the transactional network identified by the node attribute: NAICS code

(2-digit). The dark blue is the universal customer created to link with all retailers. The

colors with the most frequencies of appearance are the orange that represents the NAICS

sector 31 (Manufacturing), the lemon and the red that represents the NAICS sector 44-45

(Retail Trade). Generally, there are certain clusters in the central part of the network in

terms of the relations between firms from manufacturing sector and firms from retail

trade sector. But it is hard to clearly indentify general patterns.

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Figure 4.3 Transactional Network by NAICS Code (2-digit)

Figure 4.4 presents the transactional network indentified by firm attribute sector role.

Here, I classify four different sector roles, namely, textile provider, apparel manufacturer,

wholesaler, and retailer in apparel sector, and I also include external role to represent

firms from non-apparel industries. The dark green in the center is the universal customer

created. The red nodes are retailers that are closely circled around the universal customer.

The lemon nodes are apparel manufacturers and the pink nodes are textile providers. The

three dark blue nodes are wholesalers that appear rarest in the apparel transactional

network. The grey nodes represent external firms and they circle the periphery of the

transactional network. Overall, the different clusters by color can be identified obviously

from the graph. And there are tiers by color from the center to the edge of the

transactional network, which is consistent with the successive stages of value chains. The

graphs collectively indicate that sector role concept better captures the transactional

relations between firms than NAICS-based measure.

The network analysis yields a visualized presentation of the structure of apparel sector. It

provides visual support to the proposition that firms’ sector role dependency will predict

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major inter-firm transactions. In addition, my results further imply that the theoretical

sector role dependency concept will better predict the inter-firm relations than the

empirical relatedness measure based on NAICS.

Figure 4.4 Transactional Network by Sector Role

Figure 4.5 presents the seller-buyer design matrix structure (DMS). The X axle and Y

axle are all unique firms ranging from retailers, wholesalers, apparel manufactures, to

textile providers from upstream to downstream. Retailers are taking the numbers from1

to 33. The following numbers 34 and 35 are wholesalers. Apparel manufacturers are

taking the numbers from 36 to 190, and the rest numbers from 191 to 214 are textile

providers. Each pink dot represents the existence of a major inter-firm transaction. The

DMS graph reports the preponderance of the one-level skipping transactions from

apparel manufacturers to retailers. There are also several level-skipping transactions from

textile providers to retailers. Also, there is presence of same-level transactions between

apparel manufacturers themselves and between retailers themselves. The DMS graph

suggests the presence of vertical or tapered integration of firms.

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Number 1-33 34-35 36-190 191-214

Sector role Retailer Wholesaler Manufacturer Textile provider

Figure 4.5 Seller-Buyer Design Matrix Structure

4.1.5 Study Sample

The study sample for testing the determinants of the magnitude of major transactions

includes 599 dyads of firms that have major transactions with each other in U.S. apparel

sector from the year 1992 to 2010. It is a panel data contains observations both on

firm-level attributes and dyad-level attributes.

To address the determinants of the presence of major transactions, I need to construct a

transactional network and compute all the possible pairs of firms that have transactions

with each other. In terms of the existence of major inter-firm transactions, in essence, the

empirical component is a transactional network of linkage establishments between firms.

Buyer

Seller

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I model the possibility that a firm will have transactions with another firm and construct

adjacency matrixes to capture the relationships between firms in a transactional network.

I also include the reverse-directed dyads, that is, firm A sells to firm B is different from

firm B sells to firm A, because the transactions are directed in my study. Such a broad

definition of the dyads of firms at risk of having transactions is essential to producing

unbiased results, though; including a large number of dyads of firms that never have

transactional relations may create their own set of biases (Gulati, 1995).

Similar to my study on transactional networks, previous social network studies of tie

formation analyze every possible dyad (Podolny, 1994; Gulati, 1995; Stuart, 1998),

because they do not have any additional criteria to determine which dyads are likely to

exist and which dyads are not. Such strategy has been criticized for not accounting for

non-independence problem as each firm enters the analysis for numerous times

(Sorenson & Stuart, 2001). In addition, this strategy has another practical problem, that is,

to compute all the possible dyads is burdensome. For example, I have to create an

adjacency matrix with over one hundred thousand cells for consideration of all the

possible pairs. Sorenson and Stuart (2001) solved the problem by creating a matched

sample of potential dyad ties that did not exist while including all dyads of relations that

appear in the data. However, their results can be biased because the proportion of positive

outcomes in the sample does not match the positive outcomes in the population

(Sorenson & Stuart, 2001). In my panel data, most dyads of firms appear for certain

periods and then disappear in later years. There is no need to produce a redundant matrix

using all the unique firms appearing in the panel data over 18 years. Therefore, my

solution is to compute all the possible dyads of firms year by year, that is, to create

annual matrix (cell*cell calculation) only using unique firms for each year. My approach

substantially reduces the numerous entries of the same firms and the sample size is only

over 20,000 as opposed to 100,000. The only problem is that my sample is an unbalanced

panel data that may entail some computational and estimation issues, but most software

packages (e.g.STATA) are able to handle both balanced and unbalanced data.

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4.2 Measures

In the following section, I introduce the dependent variables, independent variable and

control variables in this study. In Table 4.4, I summarize the variables and measures.

4.2.1 Dependent Variables

My dependent variable is a measure of inter-firm transaction; I envision two alternatives

to this measure: 1) Existence of a major inter-firm transaction; 2) Magnitude (value) of a

major inter-firm transaction. The first alternative is a binary variable while the second

one is a continuous variable.

Existence of a major transaction

The first dependent variable is the existence of the link (transaction relationship) between

two firms. It is measured by the existence of a link between a seller firm and a buyer firm.

It is reported as a binary variable that takes the value of 1 when there is existence of a

link between two firms and 0 otherwise.

Magnitude of a major transaction

The second dependent variable is the size of the link measured by the value of a major

transaction between firms. The second dependent variable is a continuous variable. It is

reported as the magnitude of transaction between firm i and firm j.

4.2.2 Independent variables

Inter-firm similarity

Inter-firm similarity is measured by the proximity of 4-digit NAICS codes of two firms

that have transactions with each other. This is a categorical variable taking the value of 3

when the 4-digit NAICS codes of seller firm and buyer firm are totally the same, or

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taking the value of 2 when the 4-digit NAICS codes of seller and buyer are the same in

their first three digits, or taking the value of 1 when the 4-digit NAICS codes are the

same in their first two digits, and taking the value of 0 when the 4-digit NAICS codes of

seller and buyer are different. It is worth note that in NACIS classification, the 2-digit

codes 31-33 (31, 32, and 33) are all classified under manufacturing sector and the 2-digit

codes 44-45 are both classified under retail trade sector. In addition, the broadest valid

NAICS codes are at 2-digit level. Therefore, for instance, the proximity of NAICS codes

between a firm in industry 4481 and a firm in industry 4521 is taking the value of 1

instead of 0.

Inter-firm complementarity

Inter-firm complementarity is measured by the degree of dependency of firms’ sector

roles. This is a categorical variable taking the value of 1 when there is direct dependency

between sector roles, or taking the value of 0.5 when there is one-level indirect

dependency between sector roles, or taking the value of 0.25 when there is two-level

indirect dependency, taking the value of 0 when there is absence of dependency between

sector roles, taking the value of -1 when there is a direct backward link from downstream

to upstream, taking the value of -0.5 when there is one-level indirect backward link,

taking the value of -0.25 when there is two-level indirect backward link between two

firms. The direction of dependency relation between sector roles is supposed to from

upstream seller to downstream buyer, but there are also reversed-directional links

between firms partially due to the presence of firm integration. The following table 4.3

presents the classification of the seven different categories.

Table 4.3 Degree of Dependency of Sector Roles of Firms

Category Value Definition Example

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Direct 1 The dependency relation is from

upstream to downstream.

There is only one level-up

between the two sector roles.

Textile

Provider

Apparel

Manufacturer

Indirect

(One-level

skipping)

0.5 The dependency relation is from

upstream to downstream.

There is one-level skipping

between the two sector roles.

Apparel

Manufacturer

Wholesaler

Retailer

Indirect

(Two-level

skipping)

0.25 The dependency relation is from

upstream to downstream.

There is two-level skipping

between the two sector roles.

Textile

Provider

Apparel

Manufacturer

Wholesaler

Retailer

Absence 0 There is no dependency relation

between the sector roles.

There is a link in the same layer

of sector role.

Apparel

Manufacturer

Apparel

Manufacturer

Backward

(Two-level

skipping)

-0.25 The direction of dependency

relation is reversed.

There is a backward link from

downstream to upstream.

There is two-level skipping

between the two sector roles.

Wholesaler

Apparel

manufacturer

Retailer

Textile

provider

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Backward

(One-level

skipping)

-0.5 The direction of dependency

relation is reversed.

There is a backward link from

downstream to upstream.

There is one-level skipping

between the two sector roles. Wholesaler

Apparel

manufacturer

Retailer

Backward

(Direct)

-1 The direction of dependency

relation is reversed.

There is a backward link from

downstream to upstream.

There is only one-level up

between the two sector roles.

Textile

Provider

Apparel

Manufacturer

4.2.3 Control Variables

Besides independent variables, I control for a number of variables to ensure that my

findings are not caused by other factors that might affect the existence and the magnitude

of major transactions. The first concern is that the existence and magnitude of

transactions can be strengthened or weakened by the variations of firms’ attributes. Firm

size indicates its degree of success in the marketplace (Gulati, 1995). It is assumed that

firms with large sales and high profitability are more likely to have transactions with

other firms and much easier to attract potential transactional partners. Therefore, I control

for firm revenues of both sellers and buyers. Besides, I also control for the in-degree and

out-degree firm attributes in a major transaction.

Buyer firm revenues

Buyer firm revenue is measured by the revenue in year i for a particular buyer firm that

engage in a major transaction in year i. This explanatory variable is continuous.

Seller firm revenues

Seller firm revenue is measure by the revenue in year i for a particular seller firms that

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engage in a major transaction in year j. It is a continuous control variable.

Number seller outgoing links

I measure the outgoing links by calculating the number of transactions that a sellers have

with all other buyers in a particular year. This firm-level variable gauges the degree of a

seller firm’s capability to have major customers in a given year. By the number of

outgoing links, I control the effect that firms with lots of customers will more likely to

have a link to a specific downstream industry.

Number buyer incoming links

I measure the incoming links by calculating the number of transactions that a buyer have

with all other sellers in a certain year. This firm-level variable captures the momentum of

a buyer firm’s capability to have major transactions with seller firms. By controlling the

number of incoming links, I control the effect that firms with lots of suppliers will more

likely to have a link from a specific downstream industry

Value seller outgoing links

I measure the outgoing value by summing the total value of all transactions that a seller

have with all other buyers in a certain year. This firm-level variable captures the effect

that a firm with a great number of outgoing values is more capable of having transactions

with other firms. Alternative interpretation is that this variable controls for issues relating

to the finite capability of a seller firm to have transactions with buyer firms.

Value buyer incoming links

I measure the incoming value by summing the total value of all transactions that a buyer

have with all other sellers in a certain year. This firm-level variable captures the effect

that a firm with a large amount of incoming values is more likely to have transactions

with other firms. Another interpretation is that this variable controls for a buyer firm’s

finite capability to have transactions with suppliers.

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The second concern is that the prior transactions between two firms may lead to future

transactions. Firms tend to have transactions with their previous transactional partners

due to a variety of reasons such as established mutual trust and low communication cost.

To control for this factor, I compute two variables to capture the impact of prior links

between two firms on having subsequent transactions in later years. In addition,

including these two variables also controls for dyad-level heterogeneity.

Previous transaction

Previous transaction is a dummy variable that indicate whether two firms have prior links,

taking the value of 1 if there was previous transaction and 0 otherwise. The choice of this

variable concerns the length of time during which the previous transactional relationships

are likely to influence the current transactional links. One choice is to include all the

previous links in the transactional networks; while another possibility is to use “moving

window” (Gulati, 1995), that is to say; only transactional links established in certain

previous years will have influence on current transactional links. Considering the fact

that the repeated transactional relationships appeared periodically in my data and the

relative shortness of period observed (Gulati, 1995), I apply the first approach to include

any previous transactional link no matter when it occurred.

Previous transaction value

Previous transaction value may have influence on the existence and magnitude of

inter-firm transactions. The greater the previous transaction value between two firms, the

more likely that two firms will sustain their transactional relationship and increase future

transaction value. This control variable gauges the total value of previous transactions

between two firms.

The last concern relates to the treatment of the presence of few transactions that firms

have with themselves. The presence of same-firm transactions is contrary to my

expectation and may violate the regression estimates. Therefore, I include a dummy

variable to control for the effect.

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Same-firm transaction

Though unexpected, some firms in my study sample have major transactions with

themselves, usually with a large amount of transaction value. This binary control variable

captures whether firms having transactions with themselves, taking the value of 1 if firms

have and 0 otherwise.

Table 4.4 Summary of Variables and Measures

Variables Measures

Dependent variables Y1: Existence of major transaction

Y2: Magnitude of major transaction

Independent variables X1:Dependency degree

X2: NAICS proximity

Control variables (Firm-level)

Control variable (Dyad-level)

C1: Number seller outgoing links

C2: Number buyer incoming links

C3: Value seller outgoing links

C4: Value buyer incoming links

C5:Seller revenues

C6:Buyer revenues

C7:Previous transaction between firms

C8:Previous transaction values between

firms

C9: Same-firm transaction

4.2.4 Descriptive Statistics and Correlation Matrix

Table 4.5 presents the descriptive statistics and correlation matrix for all the variables

involved in each of the two sets of regression. The data indicates the diversity of firms.

Especially for firm attributes, the ratios of “seller revenues”, “buyer revenues”, “outgoing

links (values)”, “incoming links (values)” suggest significant variance across firms

included in my sample, notwithstanding the fact that they are all large firms involved in

major transactions. The data on “previous transaction values” points to the significant

variance across different dyads. Generally, buyers are much larger than sellers regarding

the ratio of firm revenues.

The correlation matrix suggests that “seller revenues” is highly correlated with the

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dependent variable “magnitude of major transactions” and with the dyad-level variable

“previous transaction values” between firms. And “buyer revenues” is moderately

correlated with the “value buyer incoming links”. Firms have transactions with larger

values in previous years are more likely to have transactions with larger values

subsequently. Despite high correlations in some cases, the correlations between

independent variables and control variables are generally low (below 0.3).

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Table 4.5 Descriptive Statistics and Correlation Matrix

Variables Mean S.D. Min Max DV IV1 IV2 C1 C2 C3 C4 C5 C6

Model 1 (N=23586)

DV: Existence of transaction 0.03 0.15 0 1 1.00

IV1: Dependency -0.00 0.45 -1 1 0.17 1.00

IV2:NAICS Proximity 1.29 1.19 0 3 -0.16 -0.00 1.00

C1:Outgoing values 104.28 208.67 0 1725 0.05 0.09 0.06 1.00

C2:Incoming values 109.16 333.69 0 3008 0.34 0.25 -0.23 0.05 1.00

C3:Seller revenues 5117.55 13809 0.221 137634 -0.05 -0.24 -0.24 -0.06 -0.01 1.00

C4: Buyer revenues 5128.80 13813 0.221 137634 0.32 0.24 -0.24 0.01 0.56 -0.01 1.00

C5: Previous values 7.95 121.58 0 7588 0.34 0.07 -0.06 0.15 0.16 -0.00 0.09 1.00

C6: # previous transactions 0.02 0.15 0 1 0.75 0.16 -0.15 0.05 0.32 -0.04 0.33 0.43 1.00

Variables Mean S.D. Min Max DV IV1 IV2 C1 C2 C3 C4 C5 C6 C7

Model 2 (N=599)

DV: Value of transaction 112.82 211.45 0.02 1725.85 1.00

IV1: Dependency 0.47 0.19 -1 1 -0.04 1.00

IV2:NAICS Proximity 0.11 0.46 0 3 0.23 -0.32 1.00

C1:Outgoing links 1.78 0.88 1 5 -0.13 -0.19 -0.01 1.00

C2:Incoming links 10.17 7.61 1 27 -0.12 0.03 -0.26 -0.05 1.00

C3:Seller revenues 877.03 1843.62 0.22 19176 0.88 -0.04 0.02 -0.05 -0.13 1.00

C4: Buyer revenues 32981 31784 194.19 137634 -0.11 -0.01 -0.22 -0.02 0.71 -0.11 1.00

C5: Previous values 295.35 688.06 0 8065.65 0.79 0.02 0.12 -0.09 -0.16 0.79 -0.11 1.00

C6: # previous transactions 0.78 0.41 0 1 -0.08 0.02 -0.07 -0.04 0.06 0.06 0.08 0.23 1.00

C7:Same firm 0.01 0.09 0 1 0.45 -0.23 0.57 -0.08 -0.09 0.07 -0.09 0.25 0.00 1.00

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4.3 Analytical Approach

In this section, I provide the rationale for my analytical approach and specify models

that used to test the hypotheses of the determinants of the presence and magnitude of

inter-firm major transactions.

4.3.1 Fixed Effect Models

Fixed-effect (FE) models completely ignore the between-group variation and focus

only on the within-group variation. The major advantage of FE-methods is the ability

to control for all stable characteristics of the subjects in the study, thereby eliminating

potential biases caused by time-constant unobserved heterogeneity problem (Baltagi,

2001; Wooldridge, 2002). However, FE-models have three main restrictions. First,

FE-regressions fail to estimate the effects of time-constant covariates. The

within-group transformation applies only with time-varying covariates (Wooldridge,

2002). Second, FE-models cannot estimate coefficients for variables that have no

within-subject variations. That is to say, there must be some variations in the

explanatory variables, otherwise; FE-regressions cannot estimate their effects. This is

a big problem if only a few observations show a change in an explanatory variable.

And practically, many software packages (e.g. STATA) automatically drop off the

explanatory variables with few variations in observations. Third, another disadvantage

of FE-regressions is that the number of unknown parameters increases with the

number of sample observations (Hsiao, 2007).

4.3.2 Random Effect Models

Random-effect (RE) models have become popular in a variety of disciplines ranging

from economic studies to social network studies. The main advantage of RE-estimator

is that it provides estimates for time-constant covariates. Since my study is interested

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in reporting the effects of time-invariant variables, RE-methods are more appropriate

than FE-methods to analyze my data.

Hausman (1978) indicates that FE-estimator is usually consistent regardless of the

effects are random or fixed, while RE-estimator is only efficient and consistent when

random effects are not correlated with covariates. A key assumption of the

RE-estimator is that the random effects are uncorrelated with the observed

time-constant and time-varying covariates in the model (Hausman, 1978). Sometimes,

this assumption goes untested and may result in biased estimators. Hausman test

(Hausman, 1978) is used to differentiate between FE-models and RE-models in panel

data. The null hypothesis is that the coefficients estimated by the efficient

RE-estimator are the same as the ones estimated by the consistent FE-estimator, while

the alternative is that the RE-estimator is inconsistent and therefore the FE-estimator

is preferred.

Therefore, Hausman test was applied to determine which estimator is appropriate for

my panel data. For the panel data used to test the magnitude of major transactions,

Chi-square is 6.76 (p=0.56), therefore at 95% confidence level, I fail to reject the null

hypothesis. That is to say, RE-estimator is consistent in this case. Since RE- estimator

is more efficient than FE-estimator (Wooldridge, 2002), I use RE-estimator to predict

the magnitude of major transactions. For the panel data used to test the existence of

major transactions, Chi-square is 38.01 (p=0.00), therefore at 95% confidence level, I

reject the null hypothesis. That is to say, RE-estimator is inconsistent in this case.

Therefore, FE-estimator is applied to study the existence of major transactions.

4.3.3 Statistical Technique

For studying the existence of major transactions, I use the following fixed-effect

model for panel data:

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= β + +

Where is the probability of a major transaction between firm i and firm j at time

t; β is the parameter vector; is the time-variant vector of covariates or

explanatory variables characterizing firms i and j, is the unknown intercept and

is the error term.

For studying the magnitude of major transactions, I used the following random-effect

model for panel data:

= β + + +

Where is the value of major transaction between firm i and firm j at time t; β is

the parameter vector; is the time-variant vector of covariates or explanatory

variables characterizing firm i and firm j, is the unknown intercept, is the

within-group error term, and is the between-group error term.

4.4 Descriptive Statistics

I present descriptive statistics in the following section. It provides a holistic view in

terms of the nature of my data including: 1) Trends for firms (sellers and buyers) from

manufacturing and service provider industries in apparel sector and from external

industries; 2) Number of unique NAICS codes (4-digit level) per five-year period for

sellers, buyers, and total firms; and 3) Number of transactions and value of

transactions for five-year period.

4.4.1 Data Records

The last column in this file tells the exact date when the data was inputted and

indicates that our data is tracked from 1976/11/30 to 2010/3/31. Thanks to the date

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information, Figure 4.6 demonstrates the total observations for every five years. It

shows a clear rise from 1980 to 1995 and a peak from 1991 to 1995, but the following

period from 1995 to 2010 witnessed continuous drops every five years.

Figure 4.6 Number of All Firms and Firms from Manufacturing, Service, and External

Sectors Every Five Years

Figure 4.6 also reports the number of observations from manufacturing and service

sectors. Before 1995, the number of observations from manufacturing sector has

increased continuously. The number of observations has increased by approximately

100 for every five-year period from 1976 to 1995. However, after 1995, the number of

observations from manufacturing sector has dropped gradually. The trend of number

of observations from service provider sectors is consistent with the trend of

manufacturing sector. It is worth reporting that the trend line of number of

observations from service sector was catching up with the trend line in terms of

manufacturing sector at the period from 2006 to 2010. The number of observations

from external sectors has increased all along from 1976 to 2000 and then dropped

1976-

1980

1981-

1985

1986-

1990

1991-

1995

1996-

2000

2001-

2005

2006-

2010

Manufacturing sector 181 274 378 495 446 291 212

Service sector 144 232 356 415 338 238 207

External sector 39 72 96 106 130 109 93

All sectors 364 578 830 1016 914 638 512

181 274

378

495 446

291 212

144 232

356 415

338 238 207

39 72 96 106 130 109 93

364

578

830

1016

914

638

512

0

200

400

600

800

1000

1200

Manufacturing sector Service sector

External sector All sectors

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slightly in the recent 10 years.

4.4.2 Number of Unique NAICS Codes (4-digit level) per Year

I identify number of 4-digit unique NIACS codes for sellers, buyers and total firms

for every five-year in figure 4.7. The trend lines for sellers and buyers are overlapping,

thus indicating that the numbers of unique NAICS codes for both kinds of firms are

quite close. After 2000, the trend lines of both are nearly in parallel and the number of

unique NAICS codes for buyers are always higher than the number for sellers. The

trend line for total firms is much above and number of unique NAICS for each year is

higher than numbers of unique NAICS for sellers and buyers, suggesting that sellers

and buyers appearing for every five years are from different industries at 4-digit

NAICS codes level. A limitation is that the SIC/NAICS system has evolved over this

time period.

Figure 4.7 Trend per Five Years for Number of Unique NAICS Codes (4-digit level)

of Sellers, Buyers and Total Firms

4.4.3 Number of Transactions and Value of Transactions

Among the identified 2431 transaction observations, there are 2030 observations

39

57

71

87 79

52

38

37

65

83 85 91

67 54

68

112

132

169

152

107

78

0

20

40

60

80

100

120

140

160

180

Seller NAICS

codes

Buyer NAICS

codes

Total firms

NAICS codes

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having the exact amount of transaction value. Therefore, I only include the 2030

transaction observations here to depict the trend for value of transactions in a

five-year period of time in Figure 4.8. From 1976 to 1995, the trend for total value of

transactions is continuously increasing. After 2003, there is a five-year rising trend for

total value of transactions from 2006 to 2010. The year 1996 has the highest number

of transactions with a number of 97 and the year 2008 has the largest amount of

transaction value with a total value of 9567.212. It is worth noting that the value of

transactions has not decreased that much even though the number of transactions

dropped in the decade from 2000 to 2010.

Figure 4.8 Trends for Number of Transactions and Value of Transactions

157

239

314

418 402

278 217

4974.926 7839.363

11704.976

35880.769 30407.398 28111.748

32946.612

0

10000

20000

30000

40000

0

100

200

300

400

500

1976-1980 1981-1985 1986-1990 1991-1995 1996-2000 2001-2005 2006-2010

Number of transactions Value of transactions

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5. Results

In this section, I first provide the empirical results from the analysis in terms of the

determinants of major inter-firm transactions. Then, a comparison of results from

different models is discussed. Finally, I provide the descriptive statistics regarding the

evolution of the U.S. apparel sector over the course of 30 years.

5.1 Determinants of the Presence of Inter-firm Transactions

The fixed-effect models are run by STATA 10.0 and the estimation results are reported

in Table 5.1. In Table 5.1, the dependent variable is a dummy that indicates the

existence of a major inter-firm transaction. Model 1 reports the effects of firm-level

and dyad-level control variables on the existence of major transactions. Models 2-4

present the results of the sequential introduction of independent variables of interest.

Model 5 is the full model including all independent variables and control variables.

Specifically, Model 3 tests whether there is an inverted-U shape relationship between

inter-firm similarity and the existence of major transaction.

According to Table 5.1, Hypothesis 1 is not supported. In Models 2, 3, and 5,

inter-firm similarity, as measured by NAICS proximity, is statistically significant but

is negatively associated with the existence of major transaction. Model 3 tests the

quadratic relationship between inter-firm similarity and the existence of inter-firm

transaction by introducing the squared term of NAICS proximity. It is somewhat

surprising that the results indicate that there is a U-shape relationship, rather than an

inverted-U shape relationship as hypothesized. Contrary to my expectation, the

empirical results suggest that firms that undertake more similar activities will be less

likely to have major transactions with each other. But firms within the same industry

may have transactional relations, which is inconsistent with the expectation that firms

in the same industry will compete – rather than cooperate – with each other.

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Such inconsistency with Hypothesis 1 may be explained by the existence of firms that

develop permeable boundaries that allow these firms to selectively participate at

multiple points along the value chains (Jacobides & Billinger, 2006), while engaging

in tapered integration (Harrigan, 1985). For example, two apparel manufacturers with

permeable vertical architecture can concurrently buy, sell, and ally with each other.

Moreover, an alternative explanation can be the limitation of the measure (NAICS

proximity) that SIC-based measurement does not consistently reflect relationships

among valuable resources in the ways that firms actually combine them to create

value (Bryce & Winter, 2009).

Hypothesis 2 is supported by the empirical results set out in Table 5.1. Inter-firm

complementarity, measured as firms’ sector roles dependency, is positively associated

with the existence of major inter-firm transaction. Furthermore, this independent

variable is always statistically significant at the 99% confidence level. The results are

consistent with the expectation that, from a demand perspective, there exist

dependency relations between firms’ sector roles that are defined on the basis of

complementarity in activities. The empirical results indicate that, within the vertical

structure of value chains, inter-firm relations will be hierarchically ordered with firms

providing services to final customers at the highest level, with firms manufacturing

products at the intermediate level, and with firms supplying raw materials at the

lowest level.

The dyad-level control variables generally behave as expected. The two dyad-level

variables that control for the impact of previous links between buyers and sellers are

both statistically significant. The binary variable “previous transaction” (an indicator

of whether there are previous major transactions between two firms) has a large

positive effect on the likelihood of subsequent transaction. Similarly, “previous

transaction value” is positively related to the existence of major transaction. The

larger the transaction value between two firms in the past, the more likely there will

be one or more subsequent transactions. This is not surprising because firms are

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willing to transact with past customers due to familiarity and mutual trust. In addition,

I include these two variables to capture dyad-level unobserved heterogeneity.

Table 5.1 also reports the estimation results for firm-level control variables. Not

surprisingly, “value seller outgoing links” and “value buyer incoming links” are both

statistically significant and are positively associated with the existence of major

transaction. These two variables capture the effect that firms with a large value of

outgoing/incoming links are more likely to have major transactions with

customers/suppliers. I also include two variables to control for firm size, namely

“seller revenues” and “buyer revenues.” All models show that the “seller revenues”

variable is negatively related to the existence of major transaction. Moreover, the

“buyer revenues” variable is insignificant in Models 2, 3, and 5. The results of the

firm revenues variables are inconsistent with the expectation that firms with larger

revenues are more likely to have major transactions and are better able to attract

potential partners. One of the plausible explanations can be the nature and limitations

of my data. My data are comprised of major transactions which are restricted to

situations where the sales (transaction) value to a specific buyer exceeds 10% of the

seller’s total annual revenues. In other words, the larger the seller’s revenues, the

lower the probability that the value of a particular transaction will exceed 10% of the

seller’s total annual revenues; in this situation, the transaction would not be reported

in my data. Another explanation is that firm size fails to be an appropriate predictor in

explaining firms’ likelihood to have major transactions, especially when compared

with other dyad-level predictors.

In terms of the existence of major inter-firm transactions, Hypothesis 1 is not

supported. Contrary to this hypothesis, there is a U-shape relationship between

inter-firm similarity and inter-firm transaction. Hypothesis 2 is fully supported by the

empirical results. It is worth mentioning that the control variables “previous

transaction” and “value buyer incoming links” are the strongest predictors, in

comparison with all variables.

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5.2 Determinants of the Magnitude of Inter-firm Transactions

The random-effect models are run by STATA 10.0 and the estimation results are

presented in Table 5.2. The random-effect models generate a coefficient rho, which is

an indicator of the absence or presence of heterogeneity. An estimate close to zero

implies little heterogeneity, and at all times dependence in the occurrence of major

transactions can be ascribed to the independent variables in the models (Gulati, 1995).

In my regression, the parameter rho is close to zero, thus indicating the absence of the

heterogeneity problem in my panel models. Model 1 reports the effects of firm- and

dyad-level control variables on the magnitude of major transaction. Models 2-4

present the results of the sequential introduction of independent variables. Model 5 is

the full model including all independent and control variables. Specifically, Model 3

tests the quadratic relationship between inter-firm similarity and the magnitude of

major transaction.

Hypothesis 1 states that there will be an inverted-U relationship between inter-firm

similarity and inter-firm transaction. In Model 3, the “NAICS proximity” is positive

and significant and the squared term of NAICS proximity is negative and significant,

thus indicating the presence of an inverted-U relationship between NAICS proximity

and the magnitude of major transaction. In Model 2, inter-firm similarity, measured as

NAICS proximity, is not significant, but it becomes important in the later models

when more variables are included, thus suggesting a mediation effect as a result of the

addition of new variables. In Model 5, the squared term of “NAICS proximity” is not

significant when taking into account all the variables. There is a mixed result for

Hypothesis 1 that firms will be more likely to have transactions of larger value with

similar firms, rather than with unrelated firms or with equivalent peers from the same

industry.

Hypothesis 2 is fully supported by the empirical results shown in Table 5.2. The

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coefficient of the dependency degree variable is significant and positive at the 99%

confidence level, thus indicating that inter-firm complementarity is positively

associated with the magnitude of major inter-firm transaction. In addition, the

introduction of the variable “dependency degree” increases the R^2 and the Wald

Chi^2 of the model. A comparison among models indicates that “dependency degree”

behaves better than “NAICS proximity” in predicting the dependent variable.

There are also interesting results for the control variables. First, the “previous

transaction” dummy (which is the indicator of whether there has been a prior

transaction) is insignificant across all models. The result suggests that whether there

has been a previous inter-firm transaction will not affect the magnitude of a

subsequent transaction. Such a result would be inconsistent with the expectation that a

previous transactional relationship would influence the current transaction because

firms tend to sustain the relationship and to increase future transaction value with

their old partners. The reason might be that such information may not be captured by

the major inter-firm transaction. Furthermore, in order to measure the dummy

“previous transaction,” I include all previous transactional links between firms

regardless of when they took place. However, it may be that only transactional links

established in certain prior years have an influence on the magnitude of the current

transaction. “Previous transaction value” between two firms is positively associated

with the magnitude of a major transaction. This is not surprising because firms that

had large-value transactions in previous years will subsequently sustain or strengthen

their relationship. It is worth noting that the “previous transaction value” variable

becomes less significant in later models when more variables are introduced, thus

indicating a suppresser effect by the addition of other variables. Second, the

coefficient of “number seller outgoing links” is significant but negative. It is

understandable that the size of a single transactional link will be reduced when the

number of transactional links increases, especially in terms of major transactions. As

expected, “seller revenue” is positively associated with the magnitude of major

inter-firm transaction. However, the variables “buyer revenue” and “number buyer

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incoming links” are both insignificant across models in my regression. The results

may suggest that the buyer’s attributes are not important in explaining the magnitude

of major transactions.

In terms of the magnitude of major inter-firm transaction, Hypothesis 1 and

Hypothesis 2 are both supported. Both inter-firm similarity (as measured by NAICS

proximity) and inter-firm complementarity (as measured by the degree of dependency)

are significant in explaining major inter-firm relations. Table 5.2 suggests that the

magnitude of inter-firm transactions seems to be independent of the buyer’s attributes.

The seller’s attributes are more important than the buyer’s attributes in explaining the

magnitude of major inter-firm transactions.

5.3 Comparison of Results

The empirical results of the two sets of regressions are inconsistent. Hypothesis 1 is

supported when predicting the magnitude of inter-firm transactions, but is not

supported when predicting the existence of inter-firm transactions. Surprisingly, when

predicting the existence of transaction, the expected inverted-U shape relationship is

replaced by a U-shape relationship between inter-firm similarity and inter-firm

transaction.

The inconsistency with Hypothesis 1 can be ascribed to the limitation of the

SIC-based measure to effectively capture the nature of inter-firm similarity. SIC-based

measurement has been criticized because it fails to consistently reflect relationships

among valuable resources in the ways that firms actually combine them to create

value (Bryce & Winter, 2009). In my data, the preponderance of major transactions in

apparel sector is from manufacturer to retailer. Firms from NAICS subsector 315

(Apparel Manufacturing) and firms from NAICS subsector 448 (Clothing and

Clothing Accessories Stores) are closely related, but the degree of NAICS proximity

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between firms from those two subsectors takes the value of 0. Therefore, for most of

the observations that take the value of 1 (which indicates the existence of a transaction)

for their binary dependent variable “existence of transaction,” their independent

variable “NAICS proximity” takes the value of 0. When predicting the existence of a

transaction, this problem will result in a negative coefficient of NAICS proximity

because most transactions in the apparel sector take place between firms that are in

fact related but whose connection is obscured by their positions in unrelated NAICS

industries. This unavoidably weakens the sensitivity of my data in terms of reflecting

the actual relation between inter-firm similarity and the existence of transaction. The

same problem occurs again when predicting the “magnitude of transaction.” But this

problem is mitigated because the “magnitude of transaction” is a continuous variable.

Another explanation for the unexpected U-shape relationship is the presence of

partially integrated firms. Firms develop a permeable vertical architecture that is

partly integrated and partly open to the markets along a firm’s value chain, thereby

allowing their units to make and buy simultaneously, as well as to transfer

downstream or sell (Jacobides & Billinger, 2006). Due to the benefits of vertical

permeability, firms within the same industry will have transactions with their peers in

order to effectively monitor competitors and competitively benchmark.

Hypothesis 2 is fully supported by the empirical results of both sets of regressions.

Inter-firm complementarity is always statistically significant and is positively

associated with both the existence and magnitude of major inter-firm transaction.

Overall, the results imply that inter-firm complementarity is a strong predicator in

explaining inter-firm relations and that it behaves better than inter-firm similarity in

explaining major inter-firm transactions.

There are some notable inconsistencies between the two sets of regressions regarding

the results of the control variables. First, “seller revenues” is negatively associated

with the existence of transaction, but is positively associated with the magnitude of

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transaction. This difference may be attributed to the nature of my data. The criterion

of a major transaction is that the transaction value to a specific buyer must exceed 10%

of the seller’s total annual revenues. Therefore, the larger the seller’s revenues, the

less likely it is that a single transaction will be reported as a major transaction. Second,

the results do not show a significant relationship between previous transaction and the

magnitude of current transaction. While the existence of previous transactions will

induce subsequent transactions, it does not have a significant impact on the magnitude

of subsequent transactions. Third, while the buyer’s attributes have a positive

relationship with the existence of transaction, these attributes do not have a

statistically significant impact on the magnitude of transaction. The results imply that

the seller’s and buyer’s attributes are both important in explaining the likelihood of a

transaction. Yet the magnitude of transaction seems to be related only with the seller’s

attributes while being independent of the buyer’s attributes.

Given the joint consideration of inter-firm similarity and inter-firm complementarity,

the empirical results show that the existence and magnitude of major transaction will

be a reflection of inter-firm complementarity, rather than of inter-firm similarity.

Major transactions are more likely to take place between vertically related pairs of

industries to which firms belong than between horizontally equivalent peers in similar

industries. In addition, my results imply that the theoretical sector role dependency

concept will better predict inter-firm relations than the empirical relatedness measure

based on NAICS.

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Table 5.1 Logistic Regression of the Existence of Transaction on NAICS Proximity and Dependency (N=23586)

Independent variables Model 1 Model 2 Model 3 Model 4 Model 5

Seller revenues -0.0004***

(-5.14)

-0.0004***

(-6.10)

-0.0004***

(-6.11)

-0.0004***

(-4.24)

-0.0004***

(-4.95)

Buyer revenues 0.00001**

(3.36)

0.000002

(0.78)

0.000001

(0.43)

0.00001**

(3.08)

0.000001

(0.52)

Outgoing values 0.002***

(4.33)

0.002***

(5.92)

0.002***

(5.85)

0.002***

(3.98)

0.002***

(5.20)

Incoming values 0.002***

(13.52)

0.001***

(10.36)

0.001***

(9.98)

0.002***

(12.13)

0.001***

(9.16)

Previous transaction 5.354***

(31.20)

4.799***

(27.53)

4.767***

(27.31)

5.113***

(29.78)

4.675***

(26.95)

Previous transaction values 0.0005*

(2.52)

0.0006**

(3.10)

0.0006**

(2.95)

0.0004*

(1.93)

0.0005*

(2.30)

NAICS proximity -1.247***

(-9.42)

-2.111***

(-6.60)

-2.113***

(-6.24)

NAICS proximity^2 0.375**

(3.13)

0.438**

(3.43))

Dependency degree 1.697***

(8.35)

1.336***

(4.92)

Log likelihood -1023.569 -954.492 -949.668 -986.459 -934.506

LR Chi^2 3362.38*** 3500.53*** 3510.18*** 3436.60*** 3540.50***

Note: t-value or chi-square value in parentheses; *: p<0.05; **: p<0.01; ***: p<0.001.

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Table 5.2 GLS Regression of the Magnitude of Transaction on NAICS Proximity and Dependency (N=599)

Independent variables Model 1 Model 2 Model 3 Model 4 Model 5

Seller revenues 0.091***

(41.79)

0.091***

(41.67)

0.091***

(41.85)

0.093***

(43.63)

0.094***

(43.84)

Buyer revenues -0.000003

(-0.03)

0.00001

(0.07)

0.00001

(0.10)

0.00005

(0.46)

0.00006

(0.59)

Outgoing links -12.395***

(-4.58)

-12.602***

(-4.67)

-12.283***

(-4.56)

-8.992**

(-3.38)

-8.713***

(-3.28)

Incoming links 0.696

(1.47)

0.738

(1.64)

0.826

(1.83)

0.576

(1.34)

0.769

(1.77)

Previous transaction 7.584

(1.25)

7.328

(1.21)

7.234

(1.20)

8.446

(1.45)

9.294

(1.59)

Previous transaction values 0.022***

(3.55)

0.023***

(3.67)

0.022***

(3.59)

0.016**

(2.60)

0.015*

(2.47)

Same firm 854.842***

(31.18)

844.744***

(25.70)

876.655***

(24.35)

905.264***

(32.65)

890.186***

(25.57)

NAICS proximity 2.735

(0.43)

33.932*

(2.13)

32.510*

(2.21)

NAICS proximity^2

-13.673*

(-2.14)

-8.408

(-1.35)

Dependency degree 83.681***

(6.51)

88.421***

(6.63)

Constant 28.021**

(3.38)

27.737**

(3.41)

25.459**

(3.11)

-18.979

(-1.79)

-26.672*

(-2.39)

rho 0.021 0.00 0.00 0.00 0.00

R^2 0.927 0.927 0.928 0.932 0.933

Wald Chi^2 7331.32*** 7541.31*** 7591.74*** 8122.89*** 8189.97***

Note: t-value or chi-square value in parentheses; *: p<0.05; **: p<0.01; ***: p<0.001.

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5.4 Evolution of Apparel Sector

Figure 5.1 presents the proportion of service-provider firms versus manufacturing

firms involved in major transactions in the apparel sector. According to Hypothesis 3,

over time there will be a shrinking proportion of manufacturer firms relative to

service providers involved in major transactions in the U.S. apparel sector. In the

apparel sector, value chains are dominated by retailers and marketers (Gereffi et al.,

2002; Gereffi & Frederick, 2010) that exert considerable power over wholesalers,

manufacturers, and textile providers. The competitive advantage of U.S. apparel firms

may lie in their ability to capitalize on high quality and maintain strong brand

identities (Mittelhauser, 1997), to exert substantial control over their resources and

profit distribution (Gereffi & Frederick, 2010), and to control high value-added

activities such as branding and retailing (Gereffi, 2002). Therefore, I expect to see an

increasing proportion of service activities versus manufacturing activities in the U.S.

apparel sector. This expectation is consistent with the view that the U.S. outsources

and offshores its manufacturing activities to less-developed areas in order to achieve

economic superiority by capturing the most downstream value-added (Tassey, 2010).

In Figure 5.4, from 1976 to 1990, the proportion of service firms versus

manufacturing firms has increased in every five-year period. On the other hand,

during the decade from 1991 to 2000, this proportion has decreased by 10% in each of

the component five-year periods. The decade from 2000 to 2010 witnessed a

substantial increase in service activities. Therefore, Hypothesis 3 is not fully

supported due to the mixed results. But, interestingly, my results indicate a wave

pattern in the trend associated with the proportion of service activities versus

manufacturing services over time.

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Figure 5.1 Proportion of Service Firms versus Manufacturing Firms

Figure 5.2 presents the proportion of external firms involved in transactions with

apparel firms versus all firms. Besides some low fluctuations, the percentage of

external firms versus all firms is between 11% and 12% from 1976 to 1995. In the

subsequent period from 1996 to 2010, the proportion of external firms versus all firms

has increased steadily and it peaked during the 2006-2010 period. Hypothesis 4 is

supported by the fact that over time the proportion of major transactions that involve

firms outside the apparel sector tends to increase. This is not surprising in that there is

a continuous increase in the diversification of multiple players from non-apparel

industries because products and services currently are provided by networks of firms.

Empirical results have demonstrated that apparel suppliers increasingly invest in new

information technologies, distribution systems, and other associated services in order

to respond rapidly to consumer demand while minimizing exposure to inventory risk

(Abernathy et al., 1995).

79.56% 84.67%

94.18%

83.84% 75.78%

81.79%

97.64%

0.00%

20.00%

40.00%

60.00%

80.00%

100.00%

120.00%

1976-1980 1981-1985 1986-1990 1991-1995 1996-2000 2001-2005 2006-2010

Proportion of service firms versus manufacturing firms

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Figure 5.2 Proportion of External Firms versus All Firms

Figure 5.3 shows the proportion of non-regular transactions versus regular

transactions. Regarding regular transactions, I include one-level up transactions and

transactions between apparel manufacturers and retailers.3 In terms of non-regular

transactions, I include level-skipping, same-level, and backward transactions. My

result shows that the period from 1986 to 1990 witnessed the largest percentage of

non-regular transactions relative to regular transactions. Hypothesis 5 is not fully

supported because the trend appears to be random. But my result indicates the

existence of vertically integrated or tapered integrated firms, and the fact that firms

develop permeable boundaries. This finding is consistent with previous studies that

investigate “taper integration” (Harrigan, 1984), “partically integrated firms”

(Rothaermel et al., 2006), “permeable boundaries” (Jacobides & Billinger, 2006), and

“concurrent sourcing” (Parmigiani, 2007; Parmigiani & Mitchell, 2009).

3 According to apparel sector roles’ dependency, transactions between apparel manufacturers and retailers are

one-level skipping transactions. However, in the apparel sector, such transactions should be considered regular.

10.71%

12.46% 11.57%

10.43%

14.22%

17.08% 18.16%

0.00%

2.00%

4.00%

6.00%

8.00%

10.00%

12.00%

14.00%

16.00%

18.00%

20.00%

1976-1980 1981-1985 1986-1990 1991-1995 1996-2000 2001-2005 2006-2010

Proportion of external firms versus all firms

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Figure 5.3 Proportion of Non-regular Transactions versus Regular Transactions

7.75% 9.25%

14.50%

10.39% 9.79%

12.86% 12.88%

0.00%

5.00%

10.00%

15.00%

20.00%

1976-1980 1981-1985 1986-1990 1991-1995 1996-2000 2001-2005 2006-2010

Proportion of non-regular transactions versus regular transactions

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6. Conclusion

This study investigates the nature of major transactions in the U.S. apparel sector,

using a general theory that is applicable across sectors. The firm-level analysis

provides knowledge regarding the relationship between a firm’s value chain position

and the nature of its transactions with other firms. The industry-level analysis

examines the evolution, over the course of 30 years, of the apparel sector by focusing

on the relative importance of manufacturing activities versus service activities, and on

the involvement of firms from external sectors (non-apparel sectors). Business

practitioners and journalists have provided descriptive statistics and general

knowledge regarding the nature of inter-firm relations, but these are not theory-based

and so there is little possibility of generalization to other contexts. My study is able to

predict the existence and magnitude of major transactions between firms based on

theory.

Using a unique sample of over 2,000 observations of major inter-firm transactions, I

test the theory of inter-firm similarity and of inter-firm complementarity to explain

inter-firm relations. My results suggest that inter-firm relations are a consequence of

inter-firm complementarity, rather than of inter-firm similarities. Major transactions

are more likely to take place between the vertically related pairs of industries to which

firms belong, rather than between horizontally equivalent peers in similar industries.

In the discussion below, I present the contributions and implications of this study. The

last subsection discusses limitations and future research directions.

6.1 Contributions

This study provides a systematic description of the nature of major transactions in the

U.S. apparel sector, using a theory that has the potential to apply across different

sectors. This is one of the few studies to use an important dataset to examine the

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nature and determinants of the overall network structure and the first to consider

network relations in addition to bilateral relations. This exceptional dataset has been

used by financial researchers to support their award-winning research, but it has never

been used by strategy researchers. The dataset holds great promise for examining the

structure and evolution of transactional networks across sectors over time.

In addition, this study examines the importance of the theory of inter-firm

complementarity, rather than the theory of inter-firm similarity, in explaining sector

architecture; therefore, it contributes to the literature by illuminating the positive and

statistically significant relationship between inter-firm complementarity and the

existence and magnitude of inter-firm transactions. Inter-industry similarity is

important for explaining the performance differences among firms in terms of

profitability (Rumelt, 1982), for determining the direction of firm growth and the

degree of diversification (Rumelt, 1974; Teece et al., 1994; Bryce & Winter, 2008),

and for predicting firms’ decisions to enter new markets (Lien & Klein, 2009).

Nevertheless, inter-firm similarity is not useful for predicting firms’ decisions to

establish transactional relations with other firms. My theory of inter-firm

complementarity is based on the theory presented in Dalziel’s (2007) paper, which

leads to the identification of complementary firm roles and which better predicts the

transactional relationships between firms that are critical to illuminating sector

architecture. Dalziel (2007) proposes a system-based approach to industry

classification and introduces the sector-role concept which distinguishes between

service and manufacturing subsectors, and between central and complementary firms.

My thesis is the first empirical test of the proposed theory that sectors are

hierarchically structured according to dependency relations.

Finally, my study elucidates the importance of complementarity and the limitation of

similarity in predicting inter-firm relations and hence transactional networks’ structure;

it therefore contributes to the future improvement of industry classification systems.

The current industry classification systems are built on the use of similarity in

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activities as the criterion for aggregating lower-order groups into higher-order groups.

Such systems depict sector structures as homogeneous clusters of industries but, in

practical terms, firms from complementary industries are hierarchically ordered

according to dependency relations. My findings are consistent with previous studies

that have observed the failure of current industry classification systems to reflect the

structure of the economy (Bryce & Winter, 2009; Hicks, 2011) and the failure to

capture the broad patterns in the nature of inter-firm relations that have been indicated

by researchers investigating supply chains, ecosystems, and modular clusters

(Baldwin & Clark, 2000).

6.2 Implications

Transactions are the most basic economic activities of firms and have extensive

implications on firms’ social activities and public actions in terms of international

norms, ethical standards, sustainable development, and so forth. For instance, a

buy-sell transaction between a Western retailer and manufacturing factories in

less-developed countries has implications for employee welfare, the enforcement of

building standards, and labour safety issues in poverty-stricken areas. In 2010,

Foxconn, a Taiwanese company, was plagued by a series of suicides that resulted in

14 deaths. Such out-of-the-ordinary fatalities threw an awkward spotlight on the

labour practices of Foxconn, which is a unit of Taiwan’s Hon Hai Precision Industry

Co. Ltd., whose clients include Apple Inc., Hewlett-Packard Co., and Sony Ericsson

(Reuters, 2010). In addition to the series of tragedies that occurred at Foxconn’s plants,

a series of tragedies took place in the buyer firms’ supply chains. As Foxconn’s

overseas partners, Apple, Dell, and HP were indirectly involved in the fatalities and

made statements that they would further investigate and audit the working conditions

of their Asian suppliers (Dean, 2010). Fatalities of this nature are not restricted to the

high-technology sector. Recently, public media has reported the collapse of

garment-manufacturing buildings in Bangladesh and the deaths of at least 1,100

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workers (Nolen, 2013). Western retailers and consumers who bought shirts made in

Bangladesh cannot isolate themselves from this tragedy since they are aware that their

purchasing activities and their pursuit of fast fashion and low cost to some extent

contributed to the fatalities in that country. However, this awareness is not based on

any official data pertaining to inter-firm transactions, but is instead based on reports

disseminated by the public media. Regrettably, it is only when tragedies and fatalities

take place that most people are informed of the fact that their purchasing of cheap

clothes exacts a heavy human cost.

In addition to the implications for human welfare, inter-firm transactions may also

provide information on environmental welfare and sustainable development. In order

to fully account for the environmental effects of the products and services that we

consume, we require readily accessible data on the relationships between firms in

global supply chains (Henrickson et al., 2006). In global value chains, most

developing countries concentrate their activities in lower value-added sectors such as

manufacturing and raw material industries. Developing countries have long been

blamed for their contributions to industrial pollution, especially to the rise of carbon

dioxide emissions. However, studies have suggested that the stabilization of emissions

in developed countries was partially due to the growth of imports from developing

countries (Peters et al., 2011) and have revealed the full extent of the West’s

responsibility for expanding the world’s emissions of greenhouse gases (Clark, 2009).

According to a report from Oslo’s Centre for International Climate and Environmental

Research, around 9% of total Chinese emissions are now the result of manufacturing

goods for the U.S., and around 6% are the result of producing goods for Europe.

Academics and campaigners increasingly say that responsibility for this pollution lies

with the consumer countries (Clark, 2009). Peters et al. (2011) have examined the

growth in emissions transfer via international trade from developing to developed

countries and their results indicate that international trade is a significant factor in

explaining the shift in emissions from both a production and a consumption

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perspective (Peters et al., 2011). The failure of the Copenhagen summit may partially

be explained by the fact that the developing world is reluctant to take the West’s share

of the responsibility for causing emissions by means of off-shored manufacturing

facilities aimed at producing goods for foreign markets (Clark, 2009). To solve the

issue of off-shored emissions, a new challenge is introduced because of the

measurement of domestic, exported, and imported emissions from both the production

and consumption perspectives. Relevant international-trade data of each country is

required for such meticulous measurements. Data regarding inter-firm transactions are

of benefit to the calculation of emissions from both the production and consumption

perspectives and may provide empirical evidence that can be used for the further

improvement of environmental and climate-change policies. My study calls for efforts

to improve the current industry classification systems. If industry classification

systems were designed in ways that reflect actual industry structures, as manifested by

transactions, then such systems would be an effective means of providing a superior

knowledge of industry and international-trade policies, of human-welfare issues in

manufacturing industries, and of environmental issues in raw-material industries.

Second, the findings of this study also have several important implications regarding

the evolution of U.S. apparel sector and its future governance. Some analysts have

suggested a bleak future for the U.S. apparel sector based on the erosion of domestic

employment and the increase in import penetration (Mittelhauser, 1997). It has often

been reported that the availability of high-quality jobs has been compromised by the

outsourcing of manufacturing activities (Tassey, 2010). In order to better understand

the relationship between outsourcing and employment opportunities, we also need to

consider the growth of related professional service activities. The results of my study

indicate an increasing proportion of service activities versus manufacturing activities

in the apparel sector and an increasing proportion of external firms involved in

transactions with firms in the apparel sector. The methodology employed in my study

raises the possibility that the loss of manufacturing jobs has been compensated by a

gain in service jobs. In the apparel sector, value chains are dominated by retailers and

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marketers that exert more power over wholesalers, manufacturers, and textile

providers. The competitive advantage of U.S. apparel firms may lie in their ability to

capitalize on high quality and maintain strong brand names (Mittelhauser, 1997), to

develop information integrated supply chains (Abernathy et al., 1995, 2000), to exert

substantial control over their resources and profit distribution (Gereffi & Frederick,

2010), and to control high value-added activities such as branding and retailing (Bair

& Gereffi, 2003). My study indicates a more encouraging picture of the U.S. apparel

sector than the pessimistic prognosis suggested by previous studies.

Finally, the durability of major transactions may have implications for firm

competition policies. The enduring linkages between certain large firms may indicate

the potential risk of dominance and monopoly in the market and may predict future

merger and acquisition activities.

6.3 Limitations and Future Research Directions

Despite this study’s attempt to be as thorough and rigorous as possible, there are

limitations that need to be acknowledged. First, due to the time limitation, this study

only investigates one sector. Therefore, the generalization of the findings in terms of

sector architecture and evolution in the apparel sector may not apply to other sectors.

My study is at the starting point of investigation into sector and value chain

architectures in the economy; future studies are expected to test the theory in more

complex sectors than the apparel sector. Studies on other sectors may display more

complex sector architecture, different transactional relationships, or tremendous

changes over time.

Second, the data sample of this study only contains “major transactions” rather than

the “total transactions” in the U.S. apparel sector. I believe that major transactions are

sufficient to capture the general picture of sector architecture and that large firms in

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most cases lead the trend while small firms are more likely to follow. For example,

Luo et al. (2012) investigate the transaction networks of two large sectors in Japan

and demonstrate that there are no backward linkages or cycles once the 10 largest

firms are removed from the dataset in the Japanese electronics sector. However, a

further exploration with additional data on “total transactions” will yield a more

holistic view of the structure of transaction networks. Future studies are expected to

compare the differences or similarities between the network structure of major

transactions and the network structure of minor transactions.

Moreover, this study only considers one highly developed country in North America.

Inter-firm transaction networks in the apparel sector can be very different in Asia and

South America where most firms are positioned in low value-added industries and are

engaged in manufacturing activities. Future studies are expected to explore the

apparel sector’s architecture and transactional networks in the developing world.

Finally, in terms of the theory employed in my study, I believe that it will hold for

other sectors as well. Notwithstanding the strategic behaviour of firms, differences in

business environments across regions and nations, and relentless change in technology,

there are broad and stable patterns in the nature of inter-firm relations that can be

described succinctly. Future studies are therefore expected to empirically test the same

theory in other sectors and in other countries.

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